UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM N-CSR

   CERTIFIED SHAREHOLDER REPORT OF REGISTERED MANAGEMENT INVESTMENT COMPANIES

                  Investment Company Act file number 811-06495
                                                    ----------------------------

       FLAHERTY & CRUMRINE PREFERRED INCOME OPPORTUNITY FUND INCORPORATED
--------------------------------------------------------------------------------
               (Exact name of registrant as specified in charter)

                      301 E. Colorado Boulevard, Suite 720
                               PASADENA, CA 91101
--------------------------------------------------------------------------------
               (Address of principal executive offices) (Zip code)

                               Donald F. Crumrine
                            Flaherty & Crumrine Inc.
                      301 E. Colorado Boulevard, Suite 720
                               PASADENA, CA 91101
--------------------------------------------------------------------------------
                     (Name and address of agent for service)

        registrant's telephone number, including area code: 626-795-7300
                                                           -------------

                      Date of fiscal year end: NOVEMBER 30
                                              ------------

                     Date of reporting period: MAY 31, 2006
                                              -------------


Form N-CSR is to be used by management investment companies to file reports with
the Commission not later than 10 days after the  transmission to stockholders of
any report that is required to be transmitted to  stockholders  under Rule 30e-1
under the Investment Company Act of 1940 (17 CFR 270.30e-1).  The Commission may
use the information provided on Form N-CSR in its regulatory, disclosure review,
inspection, and policymaking roles.

A registrant  is required to disclose the  information  specified by Form N-CSR,
and the  Commission  will make this  information  public.  A  registrant  is not
required to respond to the  collection  of  information  contained in Form N-CSR
unless the Form  displays a  currently  valid  Office of  Management  and Budget
("OMB")  control number.  Please direct comments  concerning the accuracy of the
information  collection  burden  estimate and any  suggestions  for reducing the
burden to  Secretary,  Securities  and Exchange  Commission,  100 F Street,  NE,
Washington,  DC 20549. The OMB has reviewed this collection of information under
the clearance requirements of 44 U.S.C. ss. 3507.






ITEM 1. REPORTS TO STOCKHOLDERS.

The Report to Shareholders is attached herewith.


                                [GRAPHIC OMITTED]

                                    LIGHTHOUSE

                               FLAHERTY & CRUMRINE
                               ===================
                                PREFERRED INCOME
                                OPPORTUNITY FUND

                                   SEMI-ANNUAL
                                     REPORT

                                  MAY 31, 2006

                             www.preferredincome.com



FLAHERTY & CRUMRINE PREFERRED INCOME OPPORTUNITY FUND

To the Shareholders of the Flaherty & Crumrine Preferred Income Opportunity Fund
("PFO"):

      The investment  environment has been challenging  during the first half of
fiscal 2006 as long-term  interest rates increased  substantially.  Despite this
challenging  environment,  we are  pleased to report the  Fund's  interest  rate
hedging  strategy  has brought the Fund  through the weak bond market to date in
relatively good shape. During the most recent fiscal quarter ended May 31st, the
Fund's total return on Net Asset Value ("NAV") declined 1.5%(1). Viewed over the
first two  fiscal  quarters  of 2006,  the total  return on NAV  INCREASED  by a
respectable  2.2%(1).  For  a  further  discussion  of  the  Fund's  recent  NAV
performance, please see the following Q&A section.

      As shown  in the  table  below,  over  longer  time  periods  the Fund has
produced  consistently strong results based on NAV. For comparison purposes,  we
have  included  the  average  total  return  earned on all  funds in the  Lipper
Domestic  Investment  Grade  Bond  Funds  category(3).  Because  the  investment
strategies including the interest rate hedge we use in the Fund typically differ
significantly  from  those of the bond  funds,  we believe  that PFO  provides a
superior way of accomplishing a similar income objective.

--------------------------------------------------------------------------------

                   TOTAL RETURN PER YEAR ON NET ASSET VALUE(1)
                         FOR PERIODS ENDED MAY 31, 2006



                                                                   ONE    THREE     FIVE     TEN     LIFE OF
                                                                  YEAR    YEARS    YEARS    YEARS    FUND(2)
                                                                  ----    -----    -----    -----    -------
                                                                                          
      Flaherty & Crumrine Preferred Income Opportunity Fund ...    0.4%     6.4%     9.9%     8.9%       9.7%
      Lipper Domestic Investment Grade Bond Funds(3) ..........    1.6%     3.9%     6.0%     6.8%       6.8%


----------
(1)   Based on data  published by Lipper Inc. in each calendar  month during the
      relevant  periods.  Distributions  are assumed to be  reinvested at NAV in
      accordance with Lipper's practice,  which differs from the procedures used
      elsewhere in this report.

(2)   Since inception on February 13, 1992.

(3)   Includes  all U.S.  Government  bond,  mortgage  bond and term  trust  and
      investment  grade bond funds in Lipper's  closed-end fund database at each
      point in time.

--------------------------------------------------------------------------------

      Long-term  interest rates have been on the rise since last September,  but
the trend accelerated during the past fiscal quarter.  We began the quarter with
yields on long-term U.S. Treasury bonds hovering around 4.6%; by the end of May,
these yields were above 5.3%.  When interest rates move like this, the impact on
bond prices is  dramatic - the price of  long-term  Treasuries  declined by more
than 9% during the quarter.

      It is  precisely  for times like these that the Fund  employs  its "safety
net" hedging  strategy.  Rising long-term  interest rates cause the value of the
Fund's investments to decline, but the Fund's interest rate hedges help moderate
the impact, limiting the net decline in the Fund's NAV.

      Recall that our hedge positions are analogous to an insurance  policy.  We
make regular "premium"



payments to buy protection  against rising long-term interest rates. In order to
keep the cost of these  payments  down, we typically  structure the hedge with a
"deductible,"  meaning  some  portion of the loss must be  absorbed  by the Fund
before we can  collect on the  policy.  If  long-term  interest  rates  increase
significantly,  the hedge  position will help offset the decline in the value of
the portfolio. This was the experience during the 2nd fiscal quarter.

      In  addition  to  helping  protect  the value of the  portfolio  in a weak
fixed-income market, the hedging strategy also helps support the Fund's dividend
through reinvestment of the hedge profits in income-producing securities. Please
see the following Q&A section for more on how the hedging  strategies affect the
Fund's NAV and distributable income.

      Good news for Fund shareholders  arrived in the recently adopted tax bill,
which  extended  the 15% and 5% tax  brackets  on  "Qualified  Dividend  Income"
("QDI") and long-term  capital  gains  through  2010.  Recall that over the last
several years,  a significant  percentage of the Fund's income has been eligible
as QDI. While we can't predict that this  percentage  will remain as high in the
future, extension of these lower brackets will certainly benefit shareholders.

      Neither  fish nor fowl,  with  characteristics  of both  debt and  equity,
preferred  securities  can serve a wide range of  financing  needs.  At the same
time, these mixed  characteristics  leave room for differing  opinions on how to
view  preferreds.  Whether  investor  or  issuer,  credit  agency or  regulator,
accountants  or the IRS; all have different  approaches  for treating  preferred
securities.  For a discussion of these mixed  characteristics and how we attempt
to benefit from them,  please take a look at the update on the preferred  market
in the following Q&A section.

      We  hope   investors   will  take   advantage   of  the  Fund's   website,
WWW.PREFERREDINCOME.COM.  It  contains  a wide  range of useful  and  up-to-date
information about the Fund. In addition,  some of the topics mentioned above are
analyzed  in greater  depth in the  Frequently  Asked  Questions  section of the
website.

      Sincerely,

      /s/ Donald F. Crumrine                      /s/ Robert M. Ettinger

      Donald F. Crumrine                          Robert M. Ettinger
      Chairman of the Board                       President

      July 10, 2006


                                        2



                               QUESTIONS & ANSWERS

WHAT WERE THE COMPONENTS OF THE FUND'S TOTAL RETURN ON NET ASSET VALUE?

      One method we have used in the past to better  communicate  the Fund's net
asset value (NAV)  performance  is to begin with the total  return on the Fund's
securities  portfolio,  and  progressively  adjust  for the  impact of  hedging,
expenses and leverage to arrive at the total return based on NAV (which includes
all of these factors). As mentioned in the shareholder's letter, the bond market
weakened  significantly  over the three months ended May 31st,  accelerating the
sell off which began last year. While preferred securities performed much better
than  long-term  U.S.  Treasuries  and many other  sectors  of the  fixed-income
market, the Fund's unhedged securities portfolio still produced a negative total
return of -2.5% during the recent fiscal quarter, and only +1.3% over the fiscal
year-to-date.

      The bright  spot so far this  fiscal year has been the degree to which the
interest rate hedge helped insulate the Fund's portfolio from a more significant
decline due to the recent rise in long-term  interest  rates.  During the Fund's
2nd fiscal quarter,  the hedge improved results by +2.1%.  During the Fund's 1st
fiscal quarter, long-term interest rates actually declined and the interest rate
hedge cost the Fund money. Consequently,  over the full fiscal year-to-date, the
hedge improved results by +1.4%.

      The  benefit of  leverage  and the cost of the Fund's  expenses  generally
offset each other to some extent, and they have again this year. However, as the
cost of the Fund's  leverage has increased  over the past two years (see the Q&A
regarding  leverage  below),  less  incremental  income on the Fund's  leveraged
investments  is available to offset the expense  burden.  In both the 2nd fiscal
quarter  and fiscal  year-to-date,  this was true.  The total  returns on NAV of
-1.5% for the quarter  and +2.2% for the fiscal  year-to-date  discussed  in the
shareholders' letter were below those of the hedged investment portfolio because
the total returns on NAV include the impact of leverage and expenses.

COULD YOU REMIND ME AGAIN THE PURPOSE OF THE INTEREST RATE HEDGE?

      The interest  rate hedge has two  purposes.  The first is to help offset a
decline in the value of the Fund's securities  portfolio (and therefore its NAV)
caused by a significant  rise in long-term  interest  rates.  The Fund purchases
out-of-the-money  put options on US Treasury  futures whose price  movements are
correlated (albeit not perfectly) with those of the Fund's securities portfolio.

      During a  period  of  rising  long-term  interest  rates,  the  Fund  will
initially  experience  a  reduction  in NAV,  as the  hedge  tightens  and  only
partially offsets the decline in the value of the securities portfolio. However,
if  interest  rates  continue  to  increase,  the  put  options  and/or  related
derivatives  would be expected to  appreciate  in value and offset an increasing
proportion  of the  decline  in the  value of the  Fund's  investments.  As with
insurance  premiums paid on a house,  these types of hedging  instruments expire
worthless  if  long-term  interest  rates  either  fall or do not  change  much,
analogous to paying for insurance when the house doesn't burn down.

      The  second  purpose of the  safety-net  hedge is to  generate  additional
income following a significant increase in long-term interest rates. This can be
achieved by investing  realized gains from the interest rate hedge in additional
income producing securities.  If long-term interest rates increase sufficiently,
the additional  income  received helps support and possibly  increase the Fund's
monthly dividend rate.


                                        3



PLEASE UPDATE ME ON DEVELOPMENTS IN THE PREFERRED MARKET.

      As we  have  previously  discussed  with  readers,  the  preferred  market
consists of two main segments -"traditional" preferred stock that pays dividends
eligible as Qualified  Dividend Income ("QDI") and taxable or "hybrid" preferred
securities that pay fully taxable interest.  These two preferred market segments
have always existed in a grey area on an issuer's balance sheet between debt and
equity, and differing viewpoints over their status have been a constant theme as
far  back as we can  remember.  Early  last  year,  Moody's  Investors  Services
attempted to reduce the  confusion by clarifying  their credit rating  treatment
for  securities  issued in each  segment.  Their doing so  prompted  significant
growth in the preferred  market,  but confusion  returned as various  regulators
(representing both issuers and purchasers) have applied different  approaches to
characterizing  these  newer  preferreds.  The  result  has been a great deal of
volatility in preferred securities' prices.

      There is nothing  unusual  going on here.  As long as clever  Wall  Street
bankers  continue to cook up variants on the two basic segments,  confusion will
persist.  And in confusion lies opportunity,  as the turmoil  contributes to the
preferred  market's  inefficiency and allows us to attempt to benefit from these
inefficiencies to add value to the Fund. Recently, we've taken advantage of this
confusion (and its impact on market valuation  relationships)  to scale back the
allocation  to  traditional  preferreds  and  increase  our  holdings  of hybrid
preferreds.  We look forward to being able to continue to take  advantage of the
preferred market's inefficiencies in the future.

ARE THERE ANY FEDERAL TAX ADVANTAGES TO INVESTING IN PREFERRED SECURITIES?

      Yes, and these  benefits have been recently  extended until 2010. The Jobs
and Growth Tax Relief  Reconciliation  Act of 2003 lowered the maximum rate paid
by individuals  on QDI to 15% or 5% (depending on an  individual's  income).  As
mentioned  in the  shareholder's  letter,  the  recently  adopted  Tax  Increase
Protection and  Reconciliation  Act of 2005 extends these lowered QDI rates from
2008 until 2010. Prior to 2003,  dividend income was typically taxed at the same
rate as ordinary income.

      To be eligible for the lower tax rate as QDI,  the  dividend  must be paid
from  a  company's  after-tax  income.  For  this  reason,  it is  important  to
understand the difference between taxable (or "hybrid") preferred securities and
traditional  preferred stock.  Hybrid preferreds pay interest,  which the issuer
can  deduct  from  revenue  in  determining  its  taxable  income.   Traditional
preferreds  pay dividends,  which are  distributed  from income after  corporate
taxes have been paid.  Because of the different tax treatment,  hybrid preferred
securities normally have a higher yield than traditional preferred stocks.

      For the investor, interest from hybrids is taxed as ordinary income, while
dividends from traditional  preferreds may be taxed at the new, lower rate. As a
result,  an investor  in a low tax bracket or an IRA  investor is more likely to
purchase taxable preferreds for the higher pre-tax income,  while an investor in
a high tax bracket may prefer the QDI issue for the higher after-tax income. But
this isn't  always the case.  The market  tends to offset the tax impact  pretty
effectively,  and securities that pay QDI will usually yield less (before taxes)
than those that pay interest.

      Of course,  it is important to remember the  composition  of the portfolio
and the income  distributions  can change from one year to the next, and the QDI
portions of one year's  distributions  may not be the same (or even  similar) to
another year's.


                                        4



DOES LEVERAGE  BENEFIT THE FUND EVEN WHEN THE U.S.  TREASURY YIELD CURVE IS FLAT
OR INVERTED?

      Yes,  as  long  as  short-term  U.S.   Treasury  interest  rates  are  not
dramatically  above long-term  rates, the Fund continues to benefit from the use
of leverage in a flat or inverted yield curve.

      Leverage is the use of borrowed funds to improve one's rate of return from
an investment with a corresponding increase in risk. PFO acquires its additional
funds to enhance the total return of the portfolio through the issuance of Money
Market Cumulative Preferred(TM) Stock (MMP(R)).

      Generally, the rate paid on the MMP(R) is well below the rate the Fund can
earn on the  investment  portfolio  and, due to a tax  advantage  for  qualified
MMP(R)  investors,  the rate the  Fund  pays on the  MMP(R)  is  relatively  low
compared with other means of financing.  The  additional  cash flow generated by
leverage  enhances  the  income  available  for  distribution  to  Common  Stock
Shareholders.

      The  incremental  income is greatest when the "spread"  between the income
generated by the portfolio and the rate paid on the MMP(R) is wide. However, the
converse is also true; as the U.S Treasury  yield curve  "flattens"  (short-term
rates and long-term rates approach  equality),  the amount of additional  income
generated by the leverage will decrease. The Fund still benefits from additional
income  generated by the leverage,  just not as much as when the Treasury  yield
curve is  steeper.  Of course,  nothing  is that  simple.  The Fund's  income is
determined by several factors, the cost of leverage being only one.

      In the case of an inverted U.S. Treasury yield curve (short-term rates are
higher than long-term rates) the Fund should continue to benefit from the use of
leverage.  Preferred  securities  generally  trade  at  yields  higher  than the
Treasury yields,  commonly referred to as the "credit spread".  So, although the
Treasury curve may be inverted,  the preferred  securities in the portfolio will
ordinarily  continue to have a higher return than the short-term  rates the Fund
pays for its leverage.

CAN I REINVEST  DIVIDENDS  DIRECTLY  INTO THE FUND AND IS THERE ANY BENEFIT OVER
PURCHASING SHARES IN THE OPEN MARKET?

      The answer to both questions is yes. The Fund's Dividend Reinvestment Plan
(the "DRIP") provides a means of acquiring additional shares of the Fund without
paying the full market premium,  if any. When the market price is above NAV, new
shares will be issued to participants in the Plan at the higher of NAV or 95% of
the then current market price.  Participating shareholders can therefore receive
a discount on their reinvested shares of up to 5% of the market price.

      If the  market  price of the shares is below the NAV,  the Plan  purchases
shares in the open market. The brokerage  commission charged for acquiring these
shares is competitive with most "discount" brokers.

      Shareholders  should be aware that not all  broker-dealers  participate in
the Fund's  dividend  reinvestment  plan. If your shares are held in a brokerage
account,  ask your broker if his/her firm is set up to participate.  If you hold
your shares in  certificate  form,  or if you would just like more  information,
call PFPC Inc., at 1-800-331-1710.

PLEASE VISIT THE  FREQUENTLY  ASKED  QUESTIONS  SECTION ON THE FUND'S WEBSITE AT
WWW.PREFERREDINCOME.COM  FOR FURTHER  DISCUSSION  ON THE ABOVE TOPICS AS WELL AS
OTHER INFORMATION ABOUT THE FUND.


                                        5



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
PORTFOLIO OVERVIEW
MAY 31, 2006 (UNAUDITED)
------------------------------------------------------------------

FUND STATISTICS ON 05/31/06
--------------------------------------------------------------------------------
Net Asset Value                                                     $     12.00

Market Price                                                        $     11.05

Discount                                                                   7.92%

Yield on Market Price                                                      7.06%

Common Shares Outstanding                                            11,695,372

INDUSTRY CATEGORIES                                               % OF PORTFOLIO
--------------------------------------------------------------------------------

                                [GRAPHIC OMITTED]

     EDGAR REPRESENTATION OF DATA POINTS USED IN PRINTED GRAPHIC AS FOLLOWS:

Utilities               38%
Banks                   25%
Insurance               14%
Finance                  9%
Oil and Gas              6%
REITs                    4%
Other                    4%

MOODY'S RATINGS                                                   % OF PORTFOLIO
--------------------------------------------------------------------------------
AAA                                                                         0.2%

AA                                                                          1.4%

A                                                                          18.3%

BBB                                                                        48.3%

BB                                                                         19.0%

Not Rated                                                                  10.9%
--------------------------------------------------------------------------------
Below Investment Grade*                                                    20.9%

*     BELOW INVESTMENT GRADE BY BOTH MOODY'S AND S&P.

                                                                         % OF
TOP 10 HOLDINGS BY ISSUER                                              PORTFOLIO
--------------------------------------------------------------------------------
Interstate Power & Light                                                 5.0%

Entergy Louisiana                                                        4.3%

Lehman Brothers                                                          3.6%

Xcel Energy                                                              3.5%

Cobank                                                                   3.0%

EOG Resources                                                            3.0%

North Fork Bancorporation                                                3.0%

HSBC                                                                     3.0%

Alabama Power                                                            2.9%

Principal Financial Group                                                2.9%



                                                                                                     % OF PORTFOLIO**
---------------------------------------------------------------------------------------------------------------------
                                                                                                        
Holdings Generating Qualified Dividend Income (QDI) for Individuals                                        68%
Holdings Generating Income Eligible for the Corporate Dividends Received Deduction (DRD)                   63%

---------------------------------------------------------------------------------------------------------------------


**    THIS DOES NOT REFLECT YEAR-END RESULTS OR ACTUAL TAX CATEGORIZATION OF
      FUND DISTRIBUTIONS. THESE PERCENTAGES CAN, AND DO, CHANGE, PERHAPS
      SIGNIFICANTLY, DEPENDING ON MARKET CONDITIONS. INVESTORS SHOULD CONSULT
      THEIR TAX ADVISOR REGARDING THEIR PERSONAL SITUATION.


                                        6



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                                        PORTFOLIO OF INVESTMENTS
                                                        MAY 31, 2006 (UNAUDITED)
              ------------------------------------------------------------------



SHARES/$ PAR                                                                                              VALUE
------------                                                                                              -----
                                                                                             
PREFERRED SECURITIES -- 94.7%
               BANKING -- 24.6%
------------------------------------------------------------------------------------------------------------------------
      20,000   ABN AMRO Capital Fund Trust V, 5.90% Pfd. ........................................  $        450,000**(1)
$  3,000,000   Astoria Capital Trust I, 9.75% 11/01/29 Capital Security, Series B ...............         3,441,750
               Auction Pass-Through Trust, CI B:
           9     Series 2006-5, Variable Rate Pfd., 144A**** ....................................           240,750*
           9     Series 2006-6, Variable Rate Pfd.,144A**** .....................................           240,750*
               Cobank, ACB:
      45,000     7.00% Pfd., 144A**** ...........................................................         2,312,100*
      75,000     Adj. Rate Pfd., 144A**** .......................................................         4,064,250*
$    500,000   Comerica (Imperial) Capital Trust I, 9.98% 12/31/26 Capital Security,
                 Series B .......................................................................           543,195
       4,500   FBOP Corporation, Adj. Rate Pfd., 144A**** .......................................         4,533,750*
$  2,250,000   First Hawaiian Capital I, 8.343% 07/01/27 Capital Security, Series B .............         2,388,240(1)
               First Republic Bank:
     200,000     6.25% Pfd. .....................................................................         4,852,000*
       5,000     6.70% Pfd. .....................................................................           123,000*
      22,500   First Republic Preferred Capital Corporation II, 8.75% Pfd., Series B, 144A**** ..           584,775
       7,400   Fleet Capital Trust VII, 7.20% Pfd. 12/15/31 .....................................           187,849
      10,000   Fleet Capital Trust VIII, 7.20% Pfd. 03/15/32 ....................................           254,950
$  4,349,000   GreenPoint Capital Trust I, 9.10% 06/01/27 Capital Security ......................         4,653,169
$  3,500,000   HBOS Capital Funding LP, 6.85% Pfd. ..............................................         3,414,145(1)
       5,000   HSBC Series II, Variable Inverse Pfd., Pvt. ......................................         5,570,000*
               HSBC USA, Inc.:
      19,500     6.50% Pfd., Series H ...........................................................           489,450*
       3,250     $2.8575 Pfd. ...................................................................           146,884*
       6,000   JPMorgan Chase Capital X, 7.00% Pfd. 02/15/32, Series J ..........................           150,360
$  1,350,000   Keycorp Institutional Capital B, 8.25% 12/15/26 Capital Security .................         1,419,322
$  1,500,000   North Fork Capital Trust I, 8.70% 12/15/26 Capital Security ......................         1,579,050
      16,000   PFGI Capital Corporation, 7.75% Pfd. .............................................           412,320
$  1,700,000   RBS Capital Trust B, 6.80% Pfd. ..................................................         1,662,591**(1)
          10   Roslyn Real Estate, 8.95% Pfd., Series C, 144A**** ...............................         1,040,969
      33,100   Sovereign Bancorp, 7.30% Pfd., Series C ..........................................           848,188*
      57,875   Sovereign Capital Trust V, 7.75% Pfd. 05/22/36 ...................................         1,455,556
       8,600   USB Capital VII, 5.875% Pfd. 08/15/35 ............................................           187,910
      56,800   USB Capital VIII, 6.35% Pfd. 12/29/65 ............................................         1,340,196
       6,000   USB Capital X, 6.50% Pfd. 04/12/66 ...............................................           143,340
$  3,100,000   Washington Mutual Preferred Funding, Variable Rate Pfd., 144A**** ................         2,976,791
-------------------------------------------------------------------------------------------------------------------
                                                                                                         51,707,600
                                                                                                   ----------------


    The accompanying notes are an integral part of the financial statements.


                                        7



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
PORTFOLIO OF INVESTMENTS (CONTINUED)
MAY 31, 2006 (UNAUDITED)
------------------------------------------------------------------



SHARES/$ PAR                                                                                            VALUE
------------                                                                                            -----
                                                                                             
PREFERRED SECURITIES -- (CONTINUED)
               FINANCIAL SERVICES -- 9.1%
---------------------------------------------------------------------------------------------------------------------
     159,505   Lehman Brothers Holdings, Inc., 5.94% Pfd., Series C .............................  $      7,590,843*
       3,000   Merrill Lynch Series II STRIPES Custodial Receipts, Pvt. .........................         2,973,000*
       9,200   Morgan Stanley Capital Trust IV, 6.25% Pfd. ......................................           213,394
     101,800   Morgan Stanley Capital Trust VI, 6.60% Pfd. ......................................         2,463,051
               SLM Corporation:
      94,150     6.97% Pfd., Series A ...........................................................         5,077,980*
       7,500     Adj. Rate Pfd., Series B .......................................................           783,750*
-------------------------------------------------------------------------------------------------------------------
                                                                                                         19,102,018
                                                                                                   ----------------
               INSURANCE -- 12.9%
---------------------------------------------------------------------------------------------------------------------
      20,000   ACE Ltd., 7.80% Pfd., Series C ...................................................           512,200**(1)
      25,000   Aegon NV, 6.50% Pfd. .............................................................           598,875**(1)
               Arch Capital Group Ltd.:
      10,000     7.875% Pfd., Series B ..........................................................           244,950**(1)
      29,750     8.00% Pfd. .....................................................................           742,114**(1)
               Axis Capital Holdings:
      55,150     7.25% Pfd., Series A ...........................................................         1,347,314**(1)
       9,300     Variable Rate Pfd., Series B ...................................................           927,489(1)
      16,000   Berkley W.R. Capital Trust II, 6.75% Pfd., 07/26/45 ..............................           371,280
      22,000   Endurance Specialty Holdings, 7.75% Pfd. .........................................           524,590**(1)
      15,850   Everest Re Capital Trust II, 6.20% Pfd., Series B ................................           337,129(1)
      10,000   Lincoln National Corporation, 6.75% Pfd. 04/20/66 ................................           237,150
     140,000   MetLife Inc., 6.50% Pfd., Series B ...............................................         3,454,500*
       4,900   PartnerRe Capital Trust I, 7.90% Pfd. 12/31/31 ...................................           124,950**(1)
       1,930   PartnerRe Ltd., 6.75% Pfd., Series C .............................................            45,008**(1)
     228,500   Principal Financial Group, 6.518% Pfd. ...........................................         6,076,957*
$  5,734,000   Provident Financing Trust I, 7.405% 03/15/38 Capital Security ....................         5,320,149
$  1,000,000   Renaissancere Capital Trust, 8.54% 03/01/27 Capital Security, Series B ...........         1,052,880(1)
               Renaissancere Holdings Ltd.:
      25,000     6.08% Pfd., Series C ...........................................................           526,250**(1)
       6,000     7.30% Pfd., Series B ...........................................................           146,040**(1)
       9,000     8.10% Pfd., Series A ...........................................................           225,450**(1)
     115,500   Scottish Re Group Ltd., 7.25% Pfd. ...............................................         2,887,500**(1)
       8,480   St. Paul Capital Trust I, 7.60% Pfd. 10/15/50 ....................................           214,290
$    560,000   USF&G Capital, 8.312% 07/01/46 Capital Security, 144A**** ........................           646,702
      22,850   XL Capital Ltd., 8.00% Pfd., Series A ............................................           585,874**(1)
-------------------------------------------------------------------------------------------------------------------
                                                                                                         27,149,641
                                                                                                   ----------------


    The accompanying notes are an integral part of the financial statements.


                                        8



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                            PORTFOLIO OF INVESTMENTS (CONTINUED)
                                                        MAY 31, 2006 (UNAUDITED)
              ------------------------------------------------------------------



SHARES/$ PAR                                                                                            VALUE
------------                                                                                            -----
                                                                                             
PREFERRED SECURITIES -- (CONTINUED)
               UTILITIES -- 37.3%
---------------------------------------------------------------------------------------------------------------------
               Alabama Power Company:
       4,980     4.60% Pfd. .....................................................................  $        404,227*
       6,485     4.72% Pfd. .....................................................................           540,136*
         868     4.92% Pfd. .....................................................................            75,360*
     225,000     5.30% Pfd. .....................................................................         5,085,000*
       6,000   Baltimore Gas & Electric Company, 6.70% Pfd., Series 1993 ........................           623,670*
       1,628   Central Hudson Gas & Electric Corporation, 4.35% Pfd., Series D, Pvt. ............           126,463*
       3,798   Central Maine Power Company, 4.75% Pfd. ..........................................           302,644*
      11,119   Central Vermont Public Service Corporation, 8.30% Sinking Fund Pfd., Pvt. ........         1,154,986*
               Connecticut Light & Power Company:
       2,050     4.50% Pfd., Series 1956 ........................................................            75,266*
      10,000     4.50% Pfd., Series 1963, Pvt. ..................................................           362,300*
      25,000     5.28% Pfd., Series 1967 ........................................................         1,082,125*
         883     $2.04 Pfd., Series 1949 ........................................................            29,395*
       2,900     $2.20 Pfd., Series 1949 ........................................................           104,110*
       9,652     $3.24 Pfd. .....................................................................           504,993*
       2,000   Consolidated Edison Company of New York, 4.65% Pfd., Series C ....................           169,320*
       7,500   Dayton Power and Light Company, 3.90% Pfd., Series C .............................           466,987*
$  1,500,000   Dominion Resources Capital Trust III, 8.40% 01/15/31 Capital Security ............         1,679,505
               Duquesne Light Company:
      15,030     3.75% Pfd. .....................................................................           462,097*
      25,775     6.50% Pfd. .....................................................................         1,313,881*
       5,000   Energy East Capital Trust I, 8.25% Pfd. ..........................................           126,575
               Entergy Arkansas, Inc.:
       2,840     4.56% Pfd. .....................................................................           205,502*
       3,050     4.56% Pfd., Series 1965 ........................................................           220,698*
       1,435     6.08% Pfd. .....................................................................           131,346*
      90,000     6.45% Pfd. .....................................................................         2,276,100*
       2,441   Entergy Gulf States, Inc., 7.56% Pfd. ............................................           224,682*
               Entergy Louisiana, Inc.:
         299     5.16% Pfd. .....................................................................            31,322*
         943     6.44% Pfd. .....................................................................            97,657*
      36,000     6.95% Pfd., 144A**** ...........................................................         3,655,080*
       4,174     7.36% Pfd. .....................................................................           434,722*
     182,383     8.00% Pfd., Series 92 ..........................................................         4,597,875*


    The accompanying notes are an integral part of the financial statements.


                                        9



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
PORTFOLIO OF INVESTMENTS (CONTINUED)
MAY 31, 2006 (UNAUDITED)
------------------------------------------------------------------



SHARES/$ PAR                                                                                            VALUE
------------                                                                                            -----
                                                                                             
PREFERRED SECURITIES -- (CONTINUED)
               UTILITIES -- (CONTINUED)
---------------------------------------------------------------------------------------------------------------------
               Entergy Mississippi, Inc.:
       4,616     4.36% Pfd. .....................................................................  $        306,295*
       5,000     4.92% Pfd. .....................................................................           374,400*
       4,400   Florida Power Company, 4.75% Pfd. ................................................           369,578*
               Great Plains Energy, Inc.:
       1,625     4.20% Pfd. .....................................................................           115,416*
       2,000     4.35% Pfd. .....................................................................           147,130*
      24,000   Gulf Power Company, 6.00% Pfd., Series 1 .........................................         2,364,720*
               Hawaiian Electric Company, Inc.:
       2,471     5.00% Pfd., Series D ...........................................................            41,686*
       7,438     5.00% Pfd., Series E ...........................................................           125,479*
       1,383     5.00% Pfd., Series I ...........................................................            23,331*
$  3,750,000   Houston Light & Power Capital Trust II, 8.257% 02/01/37 Capital Security .........         3,931,837
      30,500   Indianapolis Power & Light Company, 5.65% Pfd. ...................................         2,653,042*
     340,000   Interstate Power & Light Company, 8.375% Pfd., Series B ..........................        10,609,700*
       2,588   New York State Electric & Gas, $4.50 Pfd., Series 1949 ...........................           199,561*
               Ohio Power Company:
       3,018     4.20% Pfd. .....................................................................           223,755*
       1,251     4.40% Pfd. .....................................................................            97,165*
               Pacific Enterprises:
      13,680     $4.36 Pfd. .....................................................................         1,060,679*
      24,985     $4.50 Pfd. .....................................................................         1,999,425*
      15,730     $4.75 Pfd., Series 53 ..........................................................         1,328,634*
               Pacific Gas & Electric Co.:
       7,600     4.50% Pfd., Series H ...........................................................           141,322*
      41,500     5.00% Pfd., Series D ...........................................................           864,445*
      83,000     5.00% Pfd., Series E ...........................................................         1,772,880*
               PacifiCorp:
       5,672     $4.56 Pfd. .....................................................................           431,611*
       6,708     $4.72 Pfd. .....................................................................           528,356*
      10,500     $7.48 Sinking Fund Pfd. ........................................................         1,071,420*
       1,250   PECO Energy Company, $4.30 Pfd., Series B ........................................            92,250*
      15,142   Portland General Electric, 7.75% Sinking Fund Pfd. ...............................         1,545,922*
      14,020   Public Service Electric & Gas Company, 5.28% Pfd., Series E ......................         1,254,229*
      70,210   San Diego Gas & Electric Company, $1.70 Pfd. .....................................         1,821,247*
       8,900   Savannah Electric & Power Company, 6.00% Pfd. ....................................           225,926*


    The accompanying notes are an integral part of the financial statements.


                                       10



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                            PORTFOLIO OF INVESTMENTS (CONTINUED)
                                                        MAY 31, 2006 (UNAUDITED)
              ------------------------------------------------------------------



SHARES/$ PAR                                                                                            VALUE
------------                                                                                            -----
                                                                                             
PREFERRED SECURITIES -- (CONTINUED)
               UTILITIES -- (CONTINUED)
---------------------------------------------------------------------------------------------------------------------
               South Carolina Electric & Gas Company:
      13,974     5.125% Purchase Fund Pfd., Pvt. ................................................  $        718,124*
       7,774     6.00% Purchase Fund Pfd., Pvt. .................................................           395,774*
               Southern California Edison:
      57,646     4.08% Pfd. .....................................................................         1,003,617*
       5,000     4.24% Pfd. .....................................................................            88,950*
      60,000   Southern Union Company, 7.55% Pfd. ...............................................         1,557,900*
$    750,000   TXU Electric Capital V, 8.175% 01/30/37 Capital Security .........................           779,269
       5,700   Union Electric Company, 4.56% Pfd. ...............................................           460,246*
               Virginia Electric & Power Company:
       1,665     $4.04 Pfd. .....................................................................           116,267*
       2,470     $4.20 Pfd. .....................................................................           179,310*
       1,673     $4.80 Pfd. .....................................................................           140,013*
       2,878     $6.98 Pfd. .....................................................................           295,412*
      12,500     $7.05 Pfd. .....................................................................         1,279,063*
      11,200   Virginia Power Capital Trust, 7.375% Pfd. 07/30/42 ...............................           281,736
       2,262   Washington Gas & Light Company, $4.25 Pfd. .......................................           170,555*
      12,863   Wisconsin Power & Light Company, 6.20% Pfd. ......................................         1,318,393*
               Xcel Energy, Inc.:
      15,000     $4.08 Pfd., Series B ...........................................................         1,101,600*
      20,040     $4.10 Pfd., Series C ...........................................................         1,478,952*
      35,510     $4.11 Pfd., Series D ...........................................................         2,627,030*
      17,750     $4.16 Pfd., Series E ...........................................................         1,329,120*
      10,000     $4.56 Pfd., Series G ...........................................................           820,800*
-------------------------------------------------------------------------------------------------------------------
                                                                                                         78,427,596
                                                                                                   ----------------
               OIL AND GAS -- 4.6%
---------------------------------------------------------------------------------------------------------------------
       8,000   Devon Energy Corporation, 6.49% Pfd., Series A ...................................           803,680*
       6,125   EOG Resources, Inc., 7.195% Pfd., Series B .......................................         6,363,752*
$  1,650,000   KN Capital Trust III, 7.63% 04/15/28 Capital Security ............................         1,484,159
      10,000   Lasmo America Limited, 8.15% Pfd., 144A**** ......................................         1,069,500*(1)
-------------------------------------------------------------------------------------------------------------------
                                                                                                          9,721,091
                                                                                                   ----------------


    The accompanying notes are an integral part of the financial statements.


                                       11



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
PORTFOLIO OF INVESTMENTS (CONTINUED)
MAY 31, 2006 (UNAUDITED)
------------------------------------------------------------------



SHARES/$ PAR                                                                                            VALUE
------------                                                                                            -----
                                                                                             
PREFERRED SECURITIES -- (CONTINUED)
               REAL ESTATE INVESTMENT TRUST (REIT) -- 4.4%
---------------------------------------------------------------------------------------------------------------------
               BRE Properties, Inc.:
      20,000     6.75% Pfd., REIT, Series D .....................................................  $        474,200
      18,900     8.08% Pfd., REIT, Series B .....................................................           481,288
               Duke Realty Corporation:
      12,500     6.50% Pfd., REIT, Series K .....................................................           289,313
      20,000     6.625% Pfd., REIT, Series J ....................................................           470,500
      10,000   Equity Office Property Trust, 7.75% Pfd., REIT, Series G .........................           251,500
       1,000   Equity Residential Properties, 8.29% Pfd., REIT, Series K ........................            57,870
      50,000   HRPT Properties Trust, 7.125% Pfd., REIT, Series C ...............................         1,218,250
      10,000   PS Business Parks, Inc., 7.00% Pfd., REIT, Series H ..............................           239,300
               Public Storage, Inc.:
      13,600     6.18% Pfd., REIT, Series D .....................................................           294,644
     103,875     6.45% Pfd., REIT, Series F .....................................................         2,357,443
       7,500     6.75% Pfd., REIT, Series E .....................................................           177,450
      30,000     7.125% Pfd., REIT ..............................................................           735,000
      40,000   Realty Income Corporation, 7.375% Pfd., REIT, Series D ...........................         1,008,600
               Regency Centers Corporation:
       6,000     6.70% Pfd., REIT ...............................................................           138,600
      40,000     7.25% Pfd., REIT ...............................................................           983,400
-------------------------------------------------------------------------------------------------------------------
                                                                                                          9,177,358
                                                                                                   ----------------
               MISCELLANEOUS INDUSTRIES -- 1.8%
---------------------------------------------------------------------------------------------------------------------
      13,600   E.I. Du Pont de Nemours and Company, $4.50 Pfd., Series B ........................         1,082,900*
      35,000   Ocean Spray Cranberries, Inc., 6.25% Pfd., 144A**** ..............................         2,700,950*
      26,000   Touch America Holdings, $6.875 Pfd. ..............................................                --+*
-------------------------------------------------------------------------------------------------------------------
                                                                                                          3,783,850
                                                                                                   ----------------
               TOTAL PREFERRED SECURITIES
                 (Cost $193,129,070) ............................................................       199,069,154
                                                                                                   ----------------
CORPORATE DEBT SECURITIES -- 3.3%
               FINANCIAL SERVICES -- 0.4%
---------------------------------------------------------------------------------------------------------------------
      36,300   Saturns-GS, 6.00% 02/15/33, Series GS ............................................           805,860
---------------------------------------------------------------------------------------------------------------------


    The accompanying notes are an integral part of the financial statements.


                                       12



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                            PORTFOLIO OF INVESTMENTS (CONTINUED)
                                                        MAY 31, 2006 (UNAUDITED)
              ------------------------------------------------------------------



SHARES/$ PAR                                                                                            VALUE
------------                                                                                            -----
                                                                                             
CORPORATE DEBT SECURITIES -- (CONTINUED)
               INSURANCE -- 1.2%
---------------------------------------------------------------------------------------------------------------------
$    900,000   Farmers Exchange Capital, 7.20% 07/15/48, 144A**** ...............................  $        861,615
$  1,750,000   Liberty Mutual Insurance, 7.697%  10/15/97, 144A**** .............................         1,654,371
-------------------------------------------------------------------------------------------------------------------
                                                                                                          2,515,986
                                                                                                   ----------------
               UTILITIES -- 0.5%
---------------------------------------------------------------------------------------------------------------------
$  1,000,000   Duquesne Light Holdings, 6.25% 08/15/35 ..........................................           900,755
      10,000   Entergy Louisiana LLC, 7.60% 04/01/32 ............................................           254,250
-------------------------------------------------------------------------------------------------------------------
                                                                                                          1,155,005
                                                                                                   ----------------
               OIL AND GAS -- 1.2%
---------------------------------------------------------------------------------------------------------------------
      97,900   Nexen, Inc., 7.35% Subordinated Notes ............................................         2,461,696(1)
---------------------------------------------------------------------------------------------------------------------
               TOTAL CORPORATE DEBT SECURITIES
                 (Cost $7,263,192) ..............................................................         6,938,547
                                                                                                   ----------------
OPTION CONTRACTS -- 1.2%
       1,355   September Put Options on September U.S. Treasury Bond Futures,
                 Expiring 08/25/06 ..............................................................         2,554,609+
-------------------------------------------------------------------------------------------------------------------
               TOTAL OPTION CONTRACTS
                 (Cost $2,802,145) ..............................................................         2,554,609
                                                                                                   ----------------


    The accompanying notes are an integral part of the financial statements.


                                       13



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
PORTFOLIO OF INVESTMENTS (CONTINUED)
MAY 31, 2006 (UNAUDITED)
------------------------------------------------------------------



SHARES/$ PAR                                                                                            VALUE
------------                                                                                            -----
                                                                                          
MONEY MARKET FUND -- 0.2%
     498,837   BlackRock Provident Institutional, TempFund .................................       $        498,837
-------------------------------------------------------------------------------------------------------------------
               TOTAL MONEY MARKET FUND
                 (Cost $498,837) ...........................................................                498,837
                                                                                                   ----------------
TOTAL INVESTMENTS (Cost $203,693,244***) .......................................        99.4%           209,061,147
OTHER ASSETS AND LIABILITIES (Net) .............................................         0.6%             1,236,328
                                                                                   ---------       ----------------
TOTAL NET ASSETS AVAILABLE TO COMMON AND PREFERRED STOCK .......................       100.0%++    $    210,297,475
                                                                                   ---------       ----------------
MONEY MARKET CUMULATIVE PREFERRED(TM) STOCK (MMP(R)) REDEMPTION VALUE ......................            (70,000,000)
                                                                                                   ----------------
TOTAL NET ASSETS AVAILABLE TO COMMON STOCK .................................................       $    140,297,475
                                                                                                   ================


----------
*     Securities eligible for the Dividends Received Deduction and distributing
      Qualified Dividend Income.

**    Securities distributing Qualified Dividend Income only.

***   Aggregate cost of securities held.

****  Securities exempt from registration under Rule 144A of the Securities Act
      of 1933. These securities may be resold in transactions exempt from
      registration to qualified institutional buyers. These securities have been
      determined to be liquid under the guidelines established by the Board of
      Directors.

 (1)  Foreign Issuer.

   +  Non-income producing.

  ++  The percentage  shown for each  investment  category is the total value of
      that  category  as a  percentage  of net  assets  available  to Common and
      Preferred Stock.

        ABBREVIATIONS:

PFD. -- Preferred Securities
PVT. -- Private Placement Securities
REIT -- Real Estate Investment Trust

    The accompanying notes are an integral part of the financial statements.


                                       14



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                             STATEMENT OF ASSETS AND LIABILITIES
                                                        MAY 31, 2006 (UNAUDITED)
              ------------------------------------------------------------------


                                                                                          
ASSETS:
   Investments, at value (Cost $203,693,244) ..............................                     $ 209,061,147
   Dividends and interest receivable ......................................                         1,590,264
   Prepaid expenses .......................................................                           169,846
                                                                                                -------------
         Total Assets .....................................................                       210,821,257

LIABILITIES:
   Dividends payable to Common Stock Shareholders .........................    $    98,164
   Investment advisory fee payable ........................................        100,478
   Administration, Transfer Agent and Custodian fees payable ..............         44,786
   Professional fees payable ..............................................         41,404
   Directors' fees payable ................................................          4,575
   Accrued expenses and other payables ....................................         24,837

   Accumulated undeclared distributions to Money Market Cumulative
      Preferred(TM) Stock Shareholders ....................................        209,538
                                                                               -----------
         Total Liabilities ................................................                           523,782
                                                                                                -------------

MONEY MARKET CUMULATIVE PREFERRED(TM) STOCK (700 SHARES
   OUTSTANDING) REDEMPTION VALUE ..........................................                        70,000,000
                                                                                                -------------

NET ASSETS AVAILABLE TO COMMON STOCK ......................................                     $ 140,297,475
                                                                                                =============

NET ASSETS AVAILABLE TO COMMON STOCK consist of:
   Distributions in excess of net investment income .......................                     $    (456,456)
   Accumulated net realized gain on investments sold ......................                             5,821
   Unrealized appreciation of investments .................................                         5,367,903
   Par value of Common Stock ..............................................                           116,954
   Paid-in capital in excess of par value of Common Stock .................                       135,263,253
                                                                                                -------------
         Total Net Assets Available to Common Stock .......................                     $ 140,297,475
                                                                                                =============

NET ASSET VALUE PER SHARE OF COMMON STOCK:
   Common Stock (11,695,372 shares outstanding) ...........................                     $       12.00
                                                                                                =============


    The accompanying notes are an integral part of the financial statements.


                                       15



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
STATEMENT OF OPERATIONS
FOR THE SIX MONTHS ENDED MAY 31, 2006 (UNAUDITED)
------------------------------------------------------------------


                                                                                          
INVESTMENT INCOME:
   Dividends+ .............................................................                     $   5,658,769
   Interest ...............................................................                         1,290,220
                                                                                                -------------
         Total Investment Income ..........................................                         6,948,989

EXPENSES:
   Investment advisory fee ................................................    $   593,648
   Administrator's fee ....................................................        105,089
   Money Market Cumulative Preferred(TM) Stock broker commissions
     and auction agent fees ...............................................        100,972
   Professional fees ......................................................         63,065
   Insurance expense ......................................................         91,619
   Transfer Agent fees ....................................................         31,186
   Directors' fees ........................................................         39,130
   Custodian fees .........................................................         12,360
   Chief Compliance Officer fees ..........................................         19,694
   Other ..................................................................         41,953
         Total Expenses ...................................................                         1,098,716
                                                                                                -------------

NET INVESTMENT INCOME .....................................................                         5,850,273
                                                                                                -------------

REALIZED AND UNREALIZED GAIN/(LOSS) ON INVESTMENTS
   Net realized gain on investments sold during the period ................                         5,263,246
   Change in net unrealized appreciation/depreciation of investments
      held during the period ..............................................                        (6,666,925)
                                                                                                -------------

NET REALIZED AND UNREALIZED LOSS ON INVESTMENTS ...........................                        (1,403,679)
                                                                                                -------------

DISTRIBUTIONS TO MONEY MARKET CUMULATIVE PREFERRED(TM)
 STOCK SHAREHOLDERS:
   From net investment income (including changes in accumulated
      undeclared distributions) ...........................................                        (1,346,515)
                                                                                                -------------

NET INCREASE IN NET ASSETS TO COMMON STOCK RESULTING FROM OPERATIONS ......                     $   3,100,079
                                                                                                =============


----------
+     For Federal income tax purposes, a significant portion of this amount may
      not qualify for the inter-corporate dividends received deduction ("DRD")
      or as qualified dividend income ("QDI") for individuals.

    The accompanying notes are an integral part of the financial statements.


                                       16



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                STATEMENTS OF CHANGES IN NET ASSETS AVAILABLE TO COMMON STOCK(1)
              ------------------------------------------------------------------



                                                                               SIX MONTHS ENDED
                                                                                  MAY 31, 2006       YEAR ENDED
                                                                                  (UNAUDITED)     NOVEMBER 30, 2005
                                                                               ----------------   -----------------
                                                                                            
OPERATIONS:
   Net investment income ..................................................    $      5,850,273   $      11,145,051
   Net realized gain on investments sold during the period ................           5,263,246           4,238,243
   Change in net unrealized appreciation/depreciation of investments held
      during the period ...................................................          (6,666,925)         (4,421,911)

   Distributions to MMP(R)* Shareholders from net investment income,
      including changes in accumulated undeclared distributions ...........          (1,346,515)         (1,937,548)
                                                                               ----------------   -----------------
   NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS ...................           3,100,079           9,023,835

DISTRIBUTIONS:
   Dividends paid from net investment income to Common Stock
      Shareholders(1) .....................................................          (4,750,823)        (10,602,545)
                                                                               ----------------   -----------------
   TOTAL DISTRIBUTIONS TO COMMON STOCK SHAREHOLDERS .......................          (4,750,823)        (10,602,545)

FUND SHARE TRANSACTIONS:
   Increase from shares issued under the Dividend Reinvestment and Cash
      Purchase Plan .......................................................             231,696           1,150,181
                                                                               ----------------   -----------------
   NET INCREASE IN NET ASSETS AVAILABLE TO COMMON STOCK
      RESULTING FROM FUND SHARE TRANSACTIONS ..............................             231,696           1,150,181
                                                                               ----------------   -----------------

NET DECREASE IN NET ASSETS AVAILABLE TO COMMON STOCK FOR THE PERIOD .......    $     (1,419,048)  $        (428,529)
                                                                               ================   =================
---------------------------------------------------------------------------------------------------------------------
NET ASSETS AVAILABLE TO COMMON STOCK:
   Beginning of period ....................................................    $    141,716,523   $     142,145,052
   Net decrease in net assets during the period ...........................          (1,419,048)           (428,529)
                                                                               ----------------   -----------------
   End of period (including distributions in excess of net investment
      income of ($456,456) and ($209,391), respectively) ..................    $    140,297,475   $     141,716,523
                                                                               ================   =================


----------
*     Money Market Cumulative Preferred(TM) Stock.

(1)   May include income earned, but not paid out, in prior fiscal year.

    The accompanying notes are an integral part of the financial statements.


                                       17



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
FINANCIAL HIGHLIGHTS
FOR A COMMON SHARE OUTSTANDING THROUGHOUT EACH PERIOD.
------------------------------------------------------------------

      Contained below is per share operating  performance data, total investment
returns,  ratios to  average  net  assets  and  other  supplemental  data.  This
information  has  been  derived  from  information  provided  in  the  financial
statements and market price data for the Fund's shares.



                                                             SIX MONTHS
                                                               ENDED                         YEAR ENDED NOVEMBER 30,
                                                            MAY 31, 2006     ------------------------------------------------------
                                                            (UNAUDITED)        2005         2004      2003       2002       2001
                                                            ------------     ---------   ---------  ---------  ---------  ---------
                                                                                                        
PER SHARE OPERATING PERFORMANCE:
Net asset value, beginning of period .....................   $   12.14       $   12.27   $   12.59  $   10.78  $   11.60  $   10.68
                                                             ---------       ---------   ---------  ---------  ---------  ---------
INVESTMENT OPERATIONS:
Net investment income ....................................        0.50            0.96        0.98       1.02       1.07       1.10
Net realized and unrealized gain/(loss) on investments ...       (0.11)          (0.01)      (0.27)      1.85      (0.87)      0.89
DISTRIBUTIONS TO MMP(R)* SHAREHOLDERS:
From net investment income ...............................       (0.12)          (0.17)      (0.09)     (0.08)     (0.11)     (0.25)
                                                             ---------       ---------   ---------  ---------  ---------  ---------
Total from investment operations .........................        0.27            0.78        0.62       2.79       0.09       1.74
                                                             ---------       ---------   ---------  ---------  ---------  ---------
DISTRIBUTIONS TO COMMON STOCK SHAREHOLDERS:
From net investment income ...............................       (0.41)          (0.91)      (0.94)     (0.98)     (0.91)     (0.82)
                                                             ---------       ---------   ---------  ---------  ---------  ---------
Total distributions to Common Stock Shareholders .........       (0.41)          (0.91)      (0.94)     (0.98)     (0.91)     (0.82)
                                                             ---------       ---------   ---------  ---------  ---------  ---------
Net asset value, end of period ...........................   $   12.00       $   12.14   $   12.27  $   12.59  $   10.78  $   11.60
                                                             =========       =========   =========  =========  =========  =========
Market value, end of period ..............................   $   11.05       $   11.53   $   13.53  $   13.51  $   11.72  $   11.27
                                                             =========       =========   =========  =========  =========  =========
Total investment return based on net asset value** .......        2.34%****       6.36%       4.68%     26.57%      0.63%     16.97%
                                                             =========       =========   =========  =========  =========  =========
Total investment return based on market value ** .........       (0.78%)****     (8.40%)      7.57%     24.92%     12.61%     26.95%
                                                             =========       =========   =========  =========  =========  =========
RATIOS TO AVERAGE NET ASSETS AVAILABLE
  TO COMMON STOCK SHAREHOLDERS:
     Total net assets, end of period (in 000's) ..........   $ 140,297       $ 141,717   $ 142,145  $ 144,303  $ 122,258  $ 129,792
     Operating expenses ..................................        1.54%***        1.53%       1.52%      1.54%      1.56%      1.61%
     Net investment income + .............................        6.30%***        6.30%       7.11%      7.85%      8.67%      7.63%
----------------------------------------------------------
SUPPLEMENTAL DATA:++
     Portfolio turnover rate .............................          34%****         57%         28%        28%        29%        41%
     Total net assets available to Common and Preferred
       Stock, end of period (in 000's) ...................   $ 210,297       $ 211,717   $ 212,145  $ 214,411  $ 192,361  $ 200,228
     Ratio of operating expenses to total average net
       assets available to Common and Preferred Stock ....        1.03%***        1.03%       1.03%      1.02%      1.00%      1.03%


   *  Money Market Cumulative Preferred(TM) Stock.

  **  Assumes reinvestment of distributions at the price obtained by the Fund's
      Dividend Reinvestment and Cash Purchase Plan.

 ***  Annualized.

****  Not Annualized.

   +  The net investment income ratios reflect income net of operating  expenses
      and payments to MMP(R)* Shareholders.

  ++  Information presented under heading Supplemental Data includes MMP(R)*.

    The accompanying notes are an integral part of the financial statements.


                                       18



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                                FINANCIAL HIGHLIGHTS (CONTINUED)
                                           PER SHARE OF COMMON STOCK (UNAUDITED)
              ------------------------------------------------------------------



                                                          TOTAL                                       DIVIDEND
                                                        DIVIDENDS       NET ASSET        NYSE       REINVESTMENT
                                                          PAID            VALUE      CLOSING PRICE    PRICE (1)
                                                        ---------       ---------    -------------  ------------
                                                                                           
December 31, 2005 ..............................         $ 0.0705        $ 12.24        $ 11.09        $ 11.43
January 31, 2006 ...............................           0.0705          12.28          12.63          12.28
February 28, 2006 ..............................           0.0705          12.38          12.39          12.38
March 31, 2006 .................................           0.0650          12.25          11.46          11.54
April 30, 2006 .................................           0.0650          12.11          11.22          11.27
May 31, 2006 ...................................           0.0650          12.00          11.05          11.20


----------
(1)   Whenever the net asset value per share of the Fund's  Common Stock is less
      than or equal to the  market  price per  share on the  payment  date,  new
      shares  issued  will be valued at the higher of net asset  value or 95% of
      the then current  market  price.  Otherwise,  the  reinvestment  shares of
      Common Stock will be purchased in the open market.

    The accompanying notes are an integral part of the financial statements.


                                       19



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
FINANCIAL HIGHLIGHTS (CONTINUED)
------------------------------------------------------------------

      The  table  below  sets out  information  with  respect  to  Money  Market
Cumulative Preferred(TM) Stock currently outstanding.



                                                              INVOLUNTARY          AVERAGE
                                              ASSET           LIQUIDATING           MARKET
                      TOTAL SHARES          COVERAGE           PREFERENCE           VALUE
         DATE        OUTSTANDING (1)      PER SHARE (2)      PER SHARE (3)     PER SHARE (1)(3)
      ---------      ---------------      -------------      -------------     ----------------
                                                                       
      05/31/06*            700              $ 300,724          $ 100,000           $ 100,000
      11/30/05             700                302,788            100,000             100,000
      11/30/04             700                303,137            100,000             100,000
      11/30/03             700                306,301            100,000             100,000
      11/30/02             700                274,802            100,000             100,000
      11/30/01             700                286,040            100,000             100,000


----------
(1)   See note 6.

(2)   Calculated by  subtracting  the Fund's total  liabilities  (excluding  the
      MMP(R))  from the Fund's  total  assets and  dividing  that  amount by the
      number of MMP(R) shares outstanding.

(3)   Excludes accumulated undeclared dividends.

*     Unaudited

    The accompanying notes are an integral part of the financial statements.


                                       20



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                       NOTES TO FINANCIAL STATEMENTS (UNAUDITED)
              ------------------------------------------------------------------

1.    ORGANIZATION

      Flaherty & Crumrine  Preferred Income  Opportunity Fund  Incorporated (the
"Fund") was  incorporated  as a Maryland  corporation  on December 10, 1991, and
commenced  operations  on  February  13,  1992  as  a  diversified,   closed-end
management  investment  company  under the  Investment  Company Act of 1940,  as
amended  (the "1940  Act").  The Fund's  investment  objective is to provide its
common shareholders with high current income consistent with the preservation of
capital.

2.    SIGNIFICANT ACCOUNTING POLICIES

      The following is a summary of significant accounting policies consistently
followed  by the  Fund  in the  preparation  of its  financial  statements.  The
preparation of financial statements is in conformity with accounting  principles
generally  accepted in the United  States of America and requires  management to
make estimates and  assumptions  that affect the reported  amounts of assets and
liabilities in the financial  statements  and the reported  amounts of increases
and decreases in net assets from operations during the reporting period.  Actual
results could differ from those estimates.

      PORTFOLIO  VALUATION:  The net asset value of the Fund's  Common  Stock is
determined  by the  Fund's  Administrator  no less  frequently  than on the last
business day of each week and month.  It is  determined by dividing the value of
the  Fund's  net  assets  available  to Common  Stock by the number of shares of
Common Stock  outstanding.  The value of the Fund's net assets  attributable  to
Common  Stock is deemed to equal the value of the Fund's  total  assets less (i)
the  Fund's  liabilities  and  (ii)  the  aggregate  liquidation  value  of  the
outstanding Money Market Cumulative Preferred(TM) Stock ("MMP(R)").

      Securities  listed on a  national  securities  exchange  are valued on the
basis of the last  sale on such  exchange  on the day of  valuation,  except  as
described  hereafter.  In the  absence  of sales of listed  securities  and with
respect to (a)  securities  for which the most recent sale prices are not deemed
to represent  fair market value and (b)  unlisted  securities  (other than money
market  instruments),  securities are valued at the mean between the closing bid
and asked  prices  when quoted  prices for  investments  are readily  available.
Investments in over-the-counter  derivative  instruments,  such as interest rate
swaps and options thereon ("swaptions"),  are valued at the prices obtained from
the  broker/dealer or bank that is the counterparty to such instrument,  subject
to comparison of such valuation with a valuation  obtained from a  broker/dealer
or bank that is not a  counterparty  to the  particular  derivative  instrument.
Investments for which market  quotations are not readily  available or for which
management  determines  that the prices  are not  reflective  of current  market
conditions  are valued at fair value as determined in good faith by or under the
direction  of the  Board  of  Directors  of the  Fund,  including  reference  to
valuations of other  securities  which are  comparable in quality,  maturity and
type. Investments in money market instruments,  which mature in 60 days or less,
are valued at amortized  cost.  Investments  in money market funds are valued at
the net asset value of such funds.

      SECURITIES TRANSACTIONS AND INVESTMENT INCOME: Securities transactions are
recorded as of the trade date.  Realized gains and losses from  securities  sold
are  recorded  on the  identified  cost  basis.  Dividend  income is recorded on
ex-dividend  dates.  Interest income is recorded on the accrual basis.  The Fund
also  amortizes   premiums  and  accretes  discounts  on  certain  fixed  income
securities.


                                       21



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)
------------------------------------------------------------------

      OPTIONS:  Purchases of options are recorded as an investment, the value of
which is  marked-to-market  at each valuation  date. When the Fund enters into a
closing sale  transaction,  the Fund will record a gain or loss depending on the
difference  between the  purchase  and sale  price.  The risks  associated  with
purchasing  options and the maximum loss the Fund would incur are limited to the
purchase price originally paid.

      When the Fund writes an option, an amount equal to the premium received by
the Fund is recorded as a liability,  the value of which is  marked-to-market at
each valuation  date.  When a written option  expires,  the Fund realizes a gain
equal to the amount of the  premium  originally  received.  When the Fund enters
into a closing  purchase  transaction,  the Fund realizes a gain (or loss if the
cost of the closing purchase  transaction  exceeds the premium received when the
option  was  written)  without  regard  to any  unrealized  gain  or loss on the
underlying  security,  and the liability  related to such option is  eliminated.
When a call option is exercised,  the Fund realizes a gain or loss from the sale
of the underlying  security and the proceeds from such sale are increased by the
amount of the premium originally received.  When a put option is exercised,  the
amount of the premium  originally  received will reduce the cost of the security
which the Fund purchased upon exercise.

      The  risk in  writing  a call  option  is that the  Fund  may  forego  the
opportunity for profit if the market price of the underlying  security increases
and the option is  exercised.  The risk in writing a put option is that the Fund
may incur a loss if the market price of the  underlying  security  decreases and
the option is exercised.

      REPURCHASE  AGREEMENTS:  The  Fund  may  engage  in  repurchase  agreement
transactions. The Fund's investment adviser reviews and approves the eligibility
of the banks and dealers with which the Fund may enter into repurchase agreement
transactions.  The value of the collateral  underlying  such  transactions is at
least  equal at all times to the total  amount  of the  repurchase  obligations,
including interest.  The Fund maintains possession of the collateral through its
custodian and, in the event of counterparty  default,  the Fund has the right to
use the collateral to offset losses  incurred.  There is the possibility of loss
to the Fund in the event the Fund is delayed or prevented  from  exercising  its
rights to dispose of the collateral securities.

      FEDERAL  INCOME  TAXES:  The Fund  intends  to  continue  to  qualify as a
regulated investment company by complying with the requirements under subchapter
M of the Internal  Revenue  Code of 1986,  as amended,  applicable  to regulated
investment companies and intends to distribute  substantially all of its taxable
net  investment  income to its  shareholders.  Therefore,  no federal income tax
provision is required.

      DIVIDENDS AND  DISTRIBUTIONS TO SHAREHOLDERS:  The Fund expects to declare
dividends on a monthly basis to shareholders  of Common Stock  ("Shareholders").
Distributions  to  Shareholders  are recorded on the  ex-dividend  date. Any net
realized  short-term  capital gains will be distributed to Shareholders at least
annually.  Any net  realized  long-term  capital  gains  may be  distributed  to
Shareholders  at least  annually or may be retained by the Fund as determined by
the Fund's Board of Directors. Capital gains retained by the Fund are subject to
tax at the capital gains corporate tax rate. Subject to the Fund qualifying as a
regulated  investment  company,  any taxes paid by the Fund on such net realized
long-term  capital  gains  may be used by the  Fund's  Shareholders  as a credit
against their own tax liabilities.


                                       22



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                           NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)
              ------------------------------------------------------------------

      Income and capital gain  distributions are determined and characterized in
accordance with income tax regulations which may differ from generally  accepted
accounting  principles.  These  differences  are  primarily due to (1) differing
treatments  of income and gains on  various  investment  securities  held by the
Fund,  including  timing  differences,  (2) the attribution of expenses  against
certain components of taxable  investment  income,  and (3) federal  regulations
requiring  proportionate  allocation  of  income  and  gains to all  classes  of
shareholders.

      Distributions  from net  realized  gains  for book  purposes  may  include
short-term  capital  gains,  which  are  included  as  ordinary  income  for tax
purposes,  and may  exclude  amortization  of premium on  certain  fixed  income
securities, which are not reflected in ordinary income for tax purposes. The tax
character of distributions  paid,  including  changes in accumulated  undeclared
distributions to MMP(R) Shareholders, during 2006 and 2005 was as follows:



                     DISTRIBUTIONS PAID IN FISCAL YEAR 2006         DISTRIBUTIONS PAID IN FISCAL YEAR 2005
                     --------------------------------------         --------------------------------------
                   ORDINARY INCOME    LONG-TERM CAPITAL GAINS     ORDINARY INCOME    LONG-TERM CAPITAL GAINS
                   ---------------    -----------------------     ---------------    -----------------------
                                                                                   
Common                    N/A                   N/A                 $ 10,602,545               $ 0
Preferred                 N/A                   N/A                 $  1,937,548               $ 0


      As of November 30, 2005, the components of  distributable  earnings (i.e.,
ordinary income and capital  gain/loss)  available to Common and Preferred Stock
Shareholders, on a tax basis, were as follows:



                                     UNDISTRIBUTED               UNDISTRIBUTED               NET UNREALIZED
  CAPITAL (LOSS) CARRYFORWARD       ORDINARY INCOME             LONG-TERM GAIN        APPRECIATION/(DEPRECIATION)
  ---------------------------       ---------------             --------------        ---------------------------
                                                                                  
           ($5,431,581)                $ 222,609                     $ 0                      $ 12,208,984


      At November 30, 2005, the composition of the Fund's $5,431,581 accumulated
realized  capital losses was  $2,297,260,  $982,343,  $1,457,692 and $694,286 in
2000, 2001, 2002 and 2004, respectively. These losses may be carried forward and
offset  against any future  capital  gains through  2008,  2009,  2010 and 2012,
respectively.

      EXCISE TAX: The Internal  Revenue Code of 1986,  as amended,  imposes a 4%
nondeductible  excise tax on the Fund to the extent the Fund does not distribute
by the  end of  any  calendar  year  at  least  (1)  98% of the  sum of its  net
investment  income  for that year and its  capital  gains  (both  long-term  and
short-term)  for its fiscal  year and (2)  certain  undistributed  amounts  from
previous  years.  The Fund paid $16,000 of Federal excise taxes  attributable to
calendar year 2005 in March 2006.


                                       23



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)
------------------------------------------------------------------

3.    INVESTMENT ADVISORY FEE, ADMINISTRATION FEE, TRANSFER AGENT FEE, CUSTODIAN
      FEE,  DIRECTORS' FEES AND CHIEF COMPLIANCE OFFICER FEE

      Flaherty  & Crumrine  Incorporated  (the  "Adviser")  serves as the Fund's
investment adviser. The Fund pays the Adviser a monthly fee at an annual rate of
0.625% of the value of the Fund's average monthly total net assets  available to
Common  and  Preferred  Stock up to $100  million  and 0.50% of the value of the
Fund's average monthly total net assets  available to Common and Preferred Stock
in excess of $100 million.

      For purposes of  calculating  the fees to the Adviser,  Administrator  and
Custodian, the Fund's average weekly total managed assets means the total assets
of the Fund minus the sum of accrued  liabilities.  For purposes of  determining
total managed assets, the liquidation  preference of any preferred shares issued
by the Fund is not treated as a liability.

      PFPC  Inc.,  a member of the PNC  Financial  Services  Group,  Inc.  ("PNC
Financial Services"), serves as the Fund's Administrator. As Administrator, PFPC
Inc.  calculates the net asset value of the Fund's shares attributable to Common
Stock and  generally  assists in all  aspects of the Fund's  administration  and
operation.  As compensation for PFPC Inc.'s services as Administrator,  the Fund
pays  PFPC  Inc.  a monthly  fee at an  annual  rate of 0.10% of the first  $200
million of the Fund's  average  weekly total managed  assets,  0.04% of the next
$300 million of the Fund's  average  weekly total managed  assets,  0.03% of the
next $500 million of the Fund's average weekly total managed assets and 0.02% on
the Fund's average weekly total managed assets above $1 billion.

      PFPC Inc. also serves as the Fund's Common Stock dividend-paying agent and
registrar  (Transfer Agent). As compensation for PFPC Inc.'s services,  the Fund
pays PFPC Inc. a fee at an annual rate of 0.02% of the first $150 million of the
Fund's average weekly net assets  attributable  to Common Stock,  0.0075% of the
next $350 million of the Fund's average weekly net assets attributable to Common
Stock,  and  0.0025% of the Fund's  average  weekly net assets  attributable  to
Common Stock above $500 million,  plus certain out of pocket  expenses.  For the
purpose  of  calculating   such  fee,  the  Fund's  average  weekly  net  assets
attributable  to Common  Stock are deemed to be the average  weekly value of the
Fund's  total  assets minus the sum of the Fund's  liabilities  and  accumulated
dividends,  if any, on Fund preferred shares.  For this calculation,  the Fund's
liabilities  are deemed to include the aggregate  liquidation  preference of any
outstanding Fund preferred shares.

      PFPC Trust Company  ("PFPC Trust")  serves as the Fund's  custodian.  PFPC
Trust is an indirect subsidiary of PNC Financial  Services.  As compensation for
PFPC Trust's  services as  custodian,  the Fund pays PFPC Trust a monthly fee at
the annual rate of 0.010% of the first $200 million of the Fund's average weekly
total  managed  assets,  0.008% of the next $300  million of the Fund's  average
weekly  total  managed  assets,  0.006% of the next $500  million  of the Fund's
average  weekly total  managed  assets and 0.005% of the Fund's  average  weekly
total managed assets above $1 billion.

      The Fund  currently  pays each Director who is not a director,  officer or
employee of the Adviser a fee of $9,000 per annum,  plus $500 for each in-person
meeting of the Board of Directors or any committee  and $150 for each  telephone
meeting.  The Audit  Committee  Chairman  receives an  additional  annual fee of
$2,500.  The Fund also  reimburses  all Directors  for travel and  out-of-pocket
expenses incurred in connection with such meetings.


                                       24



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                           NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)
              ------------------------------------------------------------------

      The Fund  currently  pays the Adviser a fee of $37,500 per annum for Chief
Compliance  Officer services and reimburses  out-of-pocket  expenses incurred in
connection with providing services in this role.

4.    PURCHASES AND SALES OF SECURITIES

      For the six months ended May 31, 2006,  the cost of purchases and proceeds
from  sales  of  securities   excluding   short-term   investments,   aggregated
$75,350,913 and $70,958,520 respectively.

      At May 31, 2006,  the aggregate  cost of securities for federal income tax
purposes was $203,519,088,  the aggregate gross unrealized  appreciation for all
securities  in which  there is an excess of value over tax cost was  $12,023,570
and the aggregate  gross  unrealized  depreciation  for all  securities in which
there is an excess of tax cost over value was $6,481,511.

5.    COMMON STOCK

      At May 31, 2006,  240,000,000  shares of $0.01 par value Common Stock were
      authorized.

      Common Stock transactions were as follows:



                                                                         SIX MONTHS ENDED                  YEAR ENDED
                                                                              5/31/06                       11/30/05
                                                                       --------------------           --------------------
                                                                       SHARES        AMOUNT           SHARES        AMOUNT
                                                                       ------        ------           ------        ------
                                                                                                     
Shares issued under the Dividend Reinvestment and Cash Purchase
  Plan .............................................................   18,787     $ 231,696           90,012     $ 1,150,181
                                                                       ------     ---------          -------     -----------


6.    MONEY MARKET CUMULATIVE PREFERRED(TM) STOCK (MMP(R))

      The Fund's  Articles  of  Incorporation  authorize  the  issuance of up to
10,000,000  shares of $0.01 par value preferred  stock.  The MMP(R) is senior to
the Common Stock and results in the  financial  leveraging  of the Common Stock.
Such  leveraging  tends to magnify  both the risks and  opportunities  to Common
Stock Shareholders. Dividends on shares of MMP(R) are cumulative.

      The Fund is required to meet certain asset  coverage tests with respect to
the MMP(R).  If the Fund fails to meet these  requirements  and does not correct
such failure,  the Fund may be required to redeem, in part or in full, MMP(R) at
a redemption price of $100,000 per share plus an amount equal to the accumulated
and  unpaid  dividends  on such  shares  in  order to meet  these  requirements.
Additionally,  failure to meet the foregoing asset  requirements  could restrict
the Fund's ability to pay dividends to Common Stock  Shareholders and could lead
to sales of portfolio securities at inopportune times.

      If the Fund allocates any net gains or income ineligible for the Dividends
Received  Deduction  to  shares  of the  MMP(R),  the Fund is  required  to make
additional distributions to MMP(R) Shareholders or to pay a higher dividend rate
in amounts needed to provide a return,  net of tax, equal to the return had such
originally  paid   distributions   been  eligible  for  the  Dividends  Received
Deduction.


                                       25



--------------------------------------------------------------------------------
 Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
 NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)
-------------------------------------------------------------------

      An auction of the MMP(R) is generally held every 49 days.  Existing MMP(R)
Shareholders  may submit an order to hold,  bid or sell such shares at par value
on each auction date. MMP(R) Shareholders may also trade shares in the secondary
market, if any, between auction dates.

      At May 31, 2006,  700 shares of MMP(R) were  outstanding at the annualized
rate of 3.90%.  The dividend rate, as set by the auction  process,  is generally
expected  to vary with  short-term  interest  rates.  These  rates may vary in a
manner  unrelated to the income received on the Fund's assets,  which could have
either a beneficial or  detrimental  impact on net  investment  income and gains
available to Common Stock Shareholders.  While the Fund expects to structure its
portfolio holdings and hedging transactions to lessen such risks to Common Stock
Shareholders, there can be no assurance that such results will be attained.

7.    PORTFOLIO INVESTMENTS, CONCENTRATION AND INVESTMENT QUALITY

      The  Fund  invests  primarily  in a  diversified  portfolio  of  preferred
securities.   This  includes  traditional  preferred  stocks  eligible  for  the
inter-corporate  dividends received deduction ("DRD") and fully taxable (hybrid)
preferred securities. Under normal markets conditions, at least 80% of the value
of the Fund's net assets will be invested in preferred  securities.  Also, under
normal  market  conditions,  the Fund  invests  at least  25% of its  assets  in
securities  issued  by  companies  in the  utility  industry  and a  significant
percentage,  but no  more  than  25% of its  assets,  in  securities  issued  by
companies in the banking industry. The Fund's portfolio may therefore be subject
to  greater  risk  and  market   fluctuation  than  a  portfolio  of  securities
representing a broader range of investment alternatives.

      The Fund may  invest up to 25% of its  assets at the time of  purchase  in
securities rated below investment grade. These securities must be rated at least
either "Ba3" by Moody's  Investors  Service,  Inc. or "BB-" by Standard & Poor's
or, if unrated,  judged to be  comparable  in quality by the Adviser,  in either
case, at the time of purchase.  However,  these  securities must be issued by an
issuer having a class of senior debt rated investment grade outstanding.

      The Fund may invest up to 15% of its assets in common  stocks  and,  under
normal market conditions, up to 20% of its assets in debt securities. Certain of
its investments in hybrid,  i.e.,  fully taxable,  preferred  securities will be
subject to the  foregoing  20%  limitation to the extent that, in the opinion of
the Adviser, such investments are deemed to be debt-like in key characteristics.
Typically,  a security  will not be  considered  debt-like  (a) if an issuer can
defer payment of income for eighteen months or more without  triggering an event
of default and (b) if such issue is a junior and fully subordinated liability of
an issuer or its ultimate guarantor.

      In addition to foreign money market securities,  the Fund may invest up to
30% of its total assets in the securities of companies organized or having their
principal place of business  outside the United States.  All foreign  securities
held by the Fund will be denominated in U.S. dollars.


                                       26



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                           NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)
              ------------------------------------------------------------------

8.    SPECIAL INVESTMENT TECHNIQUES

      The Fund may employ certain  investment  techniques in accordance with its
fundamental  investment  policies.  These may include the use of when-issued and
delayed delivery transactions.  Securities purchased or sold on a when-issued or
delayed  delivery  basis may be  settled  within  45 days  after the date of the
transaction.  Such  transactions  may  expose  the  Fund to  credit  and  market
valuation  risk  greater than that  associated  with  regular  trade  settlement
procedures.  The Fund may also enter into  transactions,  in accordance with its
investment  policies,  involving  any or all of the  following:  short  sales of
securities,  futures  contracts,  interest rate swaps, swap futures,  options on
futures  contracts,   options  on  securities,   swaptions  and  certain  credit
derivative transactions, including, but not limited to, the purchase and sale of
credit  protection.  As in  the  case  of  when-issued  securities,  the  use of
over-the-counter derivatives, such as interest rate swaps, swaptions, and credit
default swaps may expose the Fund to greater credit, operations,  liquidity, and
valuation  risk than is the case with  regulated,  exchange  traded  futures and
options.   These   transactions  are  used  for  hedging  or  other  appropriate
risk-management  purposes,  or, under certain other  circumstances,  to increase
return.  No assurance  can be given that such  transactions  will achieve  their
desired purposes or will result in an overall reduction of risk to the Fund.

9.    SECURITIES LENDING

      The Fund may lend up to 15% of its total  assets  (including  the value of
the loan  collateral) to certain  qualified  brokers in order to earn additional
income. The Fund receives compensation in the form of fees or interest earned on
the  investment  of any cash  collateral  received.  The Fund also  continues to
receive  interest and  dividends on the  securities  loaned.  The Fund  receives
collateral in the form of cash or securities  with a market value at least equal
to the market value of the securities on loan,  including accrued  interest.  In
the event of default or bankruptcy by the  borrower,  the Fund could  experience
delays and costs in recovering the loaned securities or in gaining access to the
collateral.  The Fund has the right under the lending  agreement  to recover the
securities from the borrower on demand.


                                       27



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Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
ADDITIONAL INFORMATION (UNAUDITED)
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DIVIDEND REINVESTMENT AND CASH PURCHASE PLAN

      Under  the  Fund's  Dividend  Reinvestment  and Cash  Purchase  Plan  (the
"Plan"),  a shareholder  whose Common Stock is registered in their own name will
have all distributions  reinvested automatically by PFPC Inc. as agent under the
Plan, unless the shareholder elects to receive cash.  Distributions with respect
to shares  registered in the name of a broker-dealer  or other nominee (that is,
in "street  name")  may be  reinvested  by the  broker or nominee in  additional
shares  under the Plan,  but only if the  service is  provided  by the broker or
nominee,  unless the  shareholder  elects to receive  distributions  in cash.  A
shareholder  who holds Common Stock  registered in the name of a broker or other
nominee  may not be able to  transfer  the  Common  Stock to  another  broker or
nominee and continue to participate in the Plan.  Investors who own Common Stock
registered  in street name should  consult  their  broker or nominee for details
regarding reinvestment.

      The number of shares of Common Stock  distributed to  participants  in the
Plan in lieu of a cash dividend is determined in the following manner.  Whenever
the market price per share of the Fund's Common Stock is equal to or exceeds the
net asset value per share on the valuation  date,  participants in the Plan will
be issued new shares  valued at the higher of net asset value or 95% of the then
current market value. Otherwise,  PFPC Inc. will buy shares of the Fund's Common
Stock in the open market,  on the New York Stock  Exchange or  elsewhere,  on or
shortly after the payment date of the dividend or  distribution  and  continuing
until the  ex-dividend  date of the Fund's next  distribution  to holders of the
Common Stock or until it has expended  for such  purchases  all of the cash that
would otherwise be payable to the  participants.  The number of purchased shares
that will then be credited to the  participants'  accounts  will be based on the
average per share purchase price of the shares so purchased, including brokerage
commissions.  If PFPC Inc.  commences  purchases in the open market and the then
current  market price of the shares (plus any estimated  brokerage  commissions)
subsequently  exceeds their net asset value most recently  determined before the
completion of the  purchases,  PFPC Inc. will attempt to terminate  purchases in
the  open  market  and  cause  the  Fund to  issue  the  remaining  dividend  or
distribution  in shares.  In this case,  the  number of shares  received  by the
participant  will be based on the  weighted  average  of prices  paid for shares
purchased  in the  open  market  and the  price at which  the  Fund  issues  the
remaining  shares.  These  remaining  shares  will be  issued by the Fund at the
higher of net asset value or 95% of the then current market value.

      Plan participants are not subject to any charge for reinvesting  dividends
or capital gains  distributions.  Each Plan participant  will,  however,  bear a
proportionate  share of  brokerage  commissions  incurred  with  respect to PFPC
Inc.'s open market purchases in connection with the reinvestment of dividends or
capital gains  distributions.  For the six months ended May 31, 2006,  $1,086 in
brokerage commissions were incurred.

      The automatic  reinvestment  of dividends and capital gains  distributions
will not relieve Plan  participants of any income tax that may be payable on the
dividends or capital  gains  distributions.  A  participant  in the Plan will be
treated for Federal  income tax  purposes as having  received,  on the  dividend
payment date, a dividend or distribution in an amount equal to the cash that the
participant could have received instead of shares.


                                       28



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              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                  ADDITIONAL INFORMATION (UNAUDITED) (CONTINUED)
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      In addition to acquiring  shares of Common Stock through the  reinvestment
of cash  dividends  and  distributions,  a  shareholder  may invest any  further
amounts from $100 to $3,000  semi-annually  at the then current  market price in
shares purchased  through the Plan. Such semi-annual  investments are subject to
any brokerage commission charges incurred by PFPC Inc. under the Plan.

      A shareholder  whose Common Stock is registered in his or her own name may
terminate  participation  in the  Plan at any time by  notifying  PFPC  Inc.  in
writing,  by completing  the form on the back of the Plan account  statement and
forwarding it to PFPC Inc., or by calling PFPC Inc. directly. A termination will
be  effective  immediately  if notice is received by PFPC Inc.  not less than 10
days before any dividend or distribution record date. Otherwise, the termination
will be  effective,  and  only  with  respect  to any  subsequent  dividends  or
distributions,  on the first day after the  dividend  or  distribution  has been
credited to the  participant's  account in additional  shares of the Fund.  Upon
termination and according to a participant's instructions, PFPC Inc. will either
(a) issue  certificates for the whole shares credited to the shareholder's  Plan
account and a check representing any fractional shares or (b) sell the shares in
the market.  Shareholders  who hold  Common  Stock  registered  in the name of a
broker or other  nominee  should  consult  their  broker or nominee to terminate
participation.

      The  Plan is  described  in  more  detail  in the  Fund's  Plan  brochure.
Information   concerning   the  Plan  may  be   obtained   from  PFPC  Inc.   at
1-800-331-1710.

PROXY VOTING POLICIES AND PROXY VOTING RECORD ON FORM N-PX

      The Fund files Form N-PX with its complete  proxy voting record for the 12
months  ended June 30th no later than August  31st of each year.  The Fund filed
its latest Form N-PX with the  Securities  and  Exchange  Commission  ("SEC") on
August 17, 2005.  This filing,  as well as the Fund's proxy voting  policies and
procedures,  are available  (i) without  charge,  upon  request,  by calling the
Fund's  transfer  agent at  1-800-331-1710  and  (ii) on the  SEC's  website  at
WWW.SEC.GOV.  In addition,  the Fund's proxy voting  policies and procedures are
available on the Fund's website at WWW.PREFERREDINCOME.COM.

PORTFOLIO SCHEDULE ON FORM N-Q

      The Fund files a complete schedule of portfolio  holdings with the SEC for
the first and third  fiscal  quarters on Form N-Q, the latest of which was filed
for the quarter ended February 28, 2006. The Fund's Form N-Q is available on the
SEC's website at WWW.SEC.GOV or may be viewed and obtained from the SEC's Public
Reference  Room in Washington  D.C.  Information  on the operation of the Public
Reference Section may be obtained by calling 1-800-SEC-0330.


                                       29



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 Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
 ADDITIONAL INFORMATION (UNAUDITED) (CONTINUED)
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PORTFOLIO MANAGEMENT TEAM

      In managing the  day-to-day  operations of the Fund, the Adviser relies on
the  expertise  of its team of money  management  professionals,  consisting  of
Messrs. Crumrine,  Ettinger, Stone and Chadwick. The professional backgrounds of
each member of the management team are included in the  "Information  about Fund
Directors and Officers" section of this report.

CERTIFICATIONS

      Donald F. Crumrine,  as the Fund's Chief Executive Officer,  has certified
to the New York Stock Exchange that, as of May 22, 2006, he was not aware of any
violation by the Fund of applicable NYSE corporate governance listing standards.
The Fund's reports to the SEC on Forms N-CSR and N-Q contain  certifications  by
the Fund's  principal  executive  officer and principal  financial  officer that
relate to the Fund's  disclosure  in such  reports and that are required by rule
30a-2(a) under the 1940 Act.

MEETING OF SHAREHOLDERS

      On April 21, 2006, the Fund held its Annual Meeting of  Shareholders  (the
"Meeting")  for the  following  purposes:  election  of a  Director  of the Fund
("Proposal 1") and approval of an amendment to the Fund's Articles Supplementary
Creating  and  Fixing the Rights of the Money  Market  Cumulative  Preferred(TM)
Stock ("Articles Supplementary") relating to the removal of the requirement that
potential  buyers of the Fund's  Money  Market  Cumulative  Preferred(TM)  Stock
execute a  "Master  Purchaser's  Letter"  ("Proposal  2").  All  proposals  were
approved by the shareholders and the results of the voting are as follows:

PROPOSAL 1: ELECTION OF DIRECTOR.

NAME                                                   FOR           WITHHELD
----                                                   ---           --------
COMMON STOCK
David Gale .....................................    9,710,869        144,678

      Donald F.  Crumrine,  Morgan  Gust,  Karen H.  Hogan,  and  Robert F. Wulf
continue to serve in their capacities as Directors of the Fund.

PROPOSAL 2: AMENDMENT TO THE ARTICLES  SUPPLEMENTARY  RELATING TO THE REMOVAL OF
            THE MASTER PURCHASER'S LETTER REQUIREMENT

 NAME                                      FOR           AGAINST        WITHHELD
 ----                                      ---           -------        --------
COMMON STOCK ...................        9,566,627        133,518         155,402
PREFERRED STOCK ................              475             --              --


                                       30



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              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                  ADDITIONAL INFORMATION (UNAUDITED) (CONTINUED)
              ------------------------------------------------------------------

INFORMATION ABOUT FUND DIRECTORS AND OFFICERS

      The  business and affairs of the Fund are managed  under the  direction of
the Fund's Board of  Directors.  Information  pertaining  to the  Directors  and
officers of the Fund is set forth below.



                                                                        PRINCIPAL           NUMBER OF FUNDS
                                            TERM OF OFFICE            OCCUPATION(S)         IN FUND COMPLEX
NAME, ADDRESS,              POSITION(S)      AND LENGTH OF             DURING PAST             OVERSEEN       OTHER DIRECTORSHIPS
AND AGE                    HELD WITH FUND    TIME SERVED*               FIVE YEARS            BY DIRECTOR       HELD BY DIRECTOR
-------------------------- -------------- -------------------  ---------------------------- --------------- ------------------------
                                                                                            
NON-INTERESTED
DIRECTORS:

DAVID GALE                    Director     Class I Director    President & CEO of                 4        Metromedia International
Delta Dividend Group, Inc.                since January 1997   Delta Dividend                              Group, Inc.
220 Montgomery Street                                          Group, Inc. (investments).                  (telecommunications).
Suite 426                                                                                                  Flaherty & Crumrine
San Francisco, CA 94104                                                                                    Preferred Income Fund,
Age: 57                                                                                                    Flaherty & Crumrine/
                                                                                                           Claymore Preferred
                                                                                                           Securities Income Fund
                                                                                                           and Flaherty & Crumrine/
                                                                                                           Claymore Total Return
                                                                                                           Fund.

MORGAN GUST                   Director    Class III Director   President of Giant                  4        CoBiz, Inc. (financial
Giant Industries, Inc.                    since February 1992  Industries, Inc. (petroleum                  services); Flaherty &
23733 N. Scottsdale Road                                       refining and marketing) since                Crumrine Preferred
Scottsdale, AZ 85255                                           March 2002, and for more                     Income Fund, Flaherty
Age: 59                                                        than five years prior                        & Crumrine/Claymore
                                                               thereto, Executive Vice                      Preferred Securities
                                                               President, and various other                 Income Fund and Flaherty
                                                               Vice President positions at                  & Crumrine/Claymore
                                                               Giant Industries, Inc.                       Total Return Fund.

----------
*     The Fund's Board of Directors is divided into three  classes,  each class having a term of three years.  Each year the term of
      office of one class expires and the successor or successors  elected to such class serve for a three year term. The three year
      term for each class expires as follows:

                                 CLASS I DIRECTOR - three year term  expires at the  Fund's  2009  Annual  Meeting of  Shareholders;
                                 director may continue in office until his successor is duly elected and qualified.

                                 CLASS II  DIRECTORS - three year term  expires at the Fund's 2007 Annual  Meeting of  Shareholders;
                                 directors may continue in office until their successors are duly elected and qualified.

                                 CLASS III  DIRECTORS - three year term expires at the Fund's 2008 Annual  Meeting of  Shareholders;
                                 directors may continue in office until their successors are duly elected and qualified.



                                       31



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Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
ADDITIONAL INFORMATION (UNAUDITED) (CONTINUED)
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                                                                        PRINCIPAL           NUMBER OF FUNDS
                                            TERM OF OFFICE            OCCUPATION(S)         IN FUND COMPLEX
NAME, ADDRESS,              POSITION(S)      AND LENGTH OF             DURING PAST             OVERSEEN       OTHER DIRECTORSHIPS
AND AGE                    HELD WITH FUND    TIME SERVED*               FIVE YEARS            BY DIRECTOR       HELD BY DIRECTOR
-------------------------- -------------- -------------------  ---------------------------  --------------- ------------------------
                                                                                             
NON-INTERESTED
DIRECTORS:

KAREN H. HOGAN+               Director    Class III Director   Retired; Community                  4        Flaherty & Crumrine
301 E. Colorado Boulevard                  since April 2005    Volunteer; from September                    Preferred Income Fund,
Suite 720                                                      1985 to January 1997,                        Flaherty & Crumrine/
Pasadena, CA 91101                                             Senior Vice President of                     Claymore Preferred
Age: 45                                                        Preferred Stock Origination                  Securities Income Fund
                                                               at Lehman Brothers and                       and Flaherty & Crumrine/
                                                               previously, Vice President                   Claymore Total Return
                                                               of New Product Development.                  Fund.

ROBERT F. WULF                Director     Class II Director   Financial Consultant;               4        Flaherty & Crumrine
3560 Deerfield Drive South                since February 1992  Trustee, University of                       Preferred Income Fund,
Salem, OR 97302                                                Oregon Foundation;                           Flaherty & Crumrine/
Age: 69                                                        Trustee, San Francisco                       Claymore Preferred
                                                               Theological Seminary.                        Securities Income Fund
                                                                                                            and Flaherty & Crumrine/
                                                                                                            Claymore Total Return
                                                                                                            Fund.

----------
*     The Fund's Board of Directors is divided into three  classes,  each class having a term of three years.  Each year the term of
      office of one class expires and the successor or successors  elected to such class serve for a three year term. The three year
      term for each class  expires as  follows:

                                 CLASS I DIRECTOR - three year term  expires at the  Fund's  2009  Annual  Meeting of  Shareholders;
                                 director may continue in office until his successor is duly elected and qualified.

                                 CLASS II  DIRECTORS - three year term  expires at the Fund's 2007 Annual  Meeting of  Shareholders;
                                 directors may continue in office until their successors are duly elected and qualified.

                                 CLASS III  DIRECTORS - three year term expires at the Fund's 2008 Annual  Meeting of  Shareholders;
                                 directors may continue in office until their successors are duly elected and qualified.

+     As a Director, represents holders of shares of the Fund's Money Market Cumulative Preferred(TM) Stock.



                                       32



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              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                  ADDITIONAL INFORMATION (UNAUDITED) (CONTINUED)
              ------------------------------------------------------------------



                                                                        PRINCIPAL           NUMBER OF FUNDS
                                            TERM OF OFFICE            OCCUPATION(S)         IN FUND COMPLEX
NAME, ADDRESS,              POSITION(S)      AND LENGTH OF             DURING PAST             OVERSEEN       OTHER DIRECTORSHIPS
AND AGE                    HELD WITH FUND    TIME SERVED*               FIVE YEARS            BY DIRECTOR       HELD BY DIRECTOR
-------------------------- -------------- -------------------  ---------------------------- --------------- ------------------------
                                                                                             
INTERESTED
DIRECTORS:

DONALD F. CRUMRINE+, ++      Director,     Class II Director   Chairman of the Board               4        Flaherty & Crumrine
301 E. Colorado Boulevard    Chairman     since February 1992  and Director of Flaherty &                   Preferred Income Fund,
Suite 720                   of the Board                       Crumrine Incorporated.                       Flaherty & Crumrine/
Pasadena, CA 91101           and Chief                                                                      Claymore Preferred
Age: 58                      Executive                                                                      Securities Income Fund
                              Officer                                                                       and Flaherty & Crumrine/
                                                                                                            Claymore Total Return
                                                                                                            Fund.

----------
*     The Fund's Board of Directors is divided into three  classes,  each class having a term of three years.  Each year the term of
      office of one class expires and the successor or successors  elected to such class serve for a three year term. The three year
      term for each class expires as follows:

                                 CLASS I DIRECTOR - three year term  expires at the  Fund's  2009  Annual  Meeting of  Shareholders;
                                 director may continue in office until his successor is duly elected and qualified.

                                 CLASS II  DIRECTORS - three year term  expires at the Fund's 2007 Annual  Meeting of  Shareholders;
                                 directors may continue in office until their successors are duly elected and qualified.

                                 CLASS III  DIRECTORS - three year term expires at the Fund's 2008 Annual  Meeting of  Shareholders;
                                 directors may continue in office until their successors are duly elected and qualified.

+     As a Director, represents holders of shares of the Fund's Money Market Cumulative Preferred(TM) Stock.

++    "Interested  person" of the Fund as defined in the Investment  Company Act of 1940. Mr.  Crumrine is considered an "interested
      person" because of his affiliation with Flaherty & Crumrine Incorporated which acts as the Fund's investment adviser.



                                       33



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Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
ADDITIONAL INFORMATION (UNAUDITED) (CONTINUED)
------------------------------------------------------------------



                                                                               PRINCIPAL
                                               TERM OF OFFICE                OCCUPATION(S)
NAME, ADDRESS,                 POSITION(S)      AND LENGTH OF                 DURING PAST
AND AGE                      HELD WITH FUND     TIME SERVED                   FIVE YEARS
-------------------------  ------------------- -------------- --------------------------------------------
                                                     
OFFICERS:

ROBERT M. ETTINGER            President            Since      President and Director of Flaherty &
301 E. Colorado Boulevard                       October 2002  Crumrine Incorporated.
Suite 720
Pasadena, CA 91101
Age: 47

R. ERIC CHADWICK            Chief Financial        Since      Vice President and Director of Flaherty &
301 E. Colorado Boulevard   Officer, Vice       October 2002  Crumrine Incorporated; prior to August 2001,
Suite 720                     President                       portfolio manager of Flaherty & Crumrine
Pasadena, CA 91101           and Treasurer                    Incorporated.
Age: 31

CHAD C. CONWELL            Chief Compliance        Since      Chief Compliance Officer of Flaherty &
301 E. Colorado Boulevard    Officer, Vice       July 2005    Crumrine Incorporated since September
Suite 720                    President and                    2005, and since July 2005, Vice President of
Pasadena, CA 91101             Secretary                      Flaherty & Crumrine Incorporated; from
Age: 33                                                       September 1998 through June 2005,
                                                              Attorney with Paul, Hastings, Janofsky
                                                              & Walker LLP.

BRADFORD S. STONE           Vice President         Since      Vice President and Director of Flaherty &
392 Springfield Avenue      and Assistant        July 2003    Crumrine Incorporated; from June 2001
Mezzanine Suite               Treasurer                       to April 2003, Director of U.S. Market
Summit, NJ 07901                                              Strategy at Barclays Capital.

CHRISTOPHER D. RYAN         Vice President         Since      Vice President of Flaherty & Crumrine
301 E. Colorado Boulevard                        April 2005   Incorporated since February 2004;
Suite 720                                                     October 2002 to February 2004, Product
Pasadena, CA 91101                                            Analyst of Flaherty & Crumrine Incorporated.
Age: 38                                                       From 1999 to 2002, graduate student.

LAURIE C. LODOLO               Assistant           Since      Assistant Compliance Officer of Flaherty &
301 E. Colorado Boulevard     Compliance         July 2004    Crumrine Incorporated since August 2004;
Suite 720                  Officer, Assistant                 since February 2004, Secretary of Flaherty
Pasadena, CA 91101           Treasurer and                    & Crumrine Incorporated; since January
Age: 42                    Assistant Secretary                1987, Account Administrator of Flaherty &
                                                              Crumrine Incorporated.



                                       34



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              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                  ADDITIONAL INFORMATION (UNAUDITED) (CONTINUED)
              ------------------------------------------------------------------

BOARD CONSIDERATION AND APPROVAL OF CONTINUANCE OF INVESTMENT ADVISORY AGREEMENT

      During the six month period ended May 31, 2006,  the Board of Directors of
the Fund approved the continuation of the investment advisory agreement with the
Adviser (the  "Agreement").  The  following  paragraphs  summarize  the material
information  and factors  considered  by the Board,  including  the  Independent
Directors, as well as their conclusions relative to such factors.

NATURE, EXTENT AND QUALITY OF SERVICES

      The Board members reviewed in detail the nature and extent of the services
provided by the Adviser and the quality of those services over the past year and
since inception.  The Board members noted that these services  included managing
the Fund's investment program, as well as providing  significant  administrative
services  beyond what the Agreement  required.  The Board members noted that the
Adviser also provided,  generally at its expense:  office  facilities for use by
the  Fund;   personnel   responsible   for   supervising   the   performance  of
administrative,  accounting  and related  services;  and  investment  compliance
monitoring.  The Board members also  considered  the Adviser's  sound  financial
condition  and the Adviser's  commitment  to its  business,  as evidenced by its
hiring  additional  personnel  as the  business  has  grown.  The Board  members
evaluated the Adviser's  services  based on their direct  experience  serving as
Directors  for  many  years,  focusing  on (i) the  Adviser's  knowledge  of the
preferred  securities market generally and the sophisticated  hedging strategies
the Fund employs and (ii) the Adviser's culture of compliance. The Board members
reviewed  the  personnel  responsible  for  providing  services  to the Fund and
observed that, based on their  experience and interaction with the Adviser:  (1)
the Adviser's personnel exhibited a high level of personal integrity,  diligence
and  attention  to  detail in  carrying  out  their  responsibilities  under the
Agreement;  (2) the  Adviser  was  responsive  to  requests of the Board and its
personnel were available  between Board meetings to answer  questions from Board
members;  and (3) the  Adviser  had  kept the  Board  apprised  of  developments
relating to the Fund. The Board members also  considered  the continued  efforts
undertaken by the Adviser to maintain an effective compliance program. The Board
members  concluded  that the  nature and extent of the  services  provided  were
reasonable  and  appropriate  in  relation  to the Fund's  investment  goals and
strategies, the corporate and regulatory environment in which the Fund operates,
and the level of services  provided by the Adviser,  and that the quality of the
Adviser's service continues to be high.

INVESTMENT PERFORMANCE

      The Board  members  considered  the Fund's  performance  since  inception,
including its  performance in recent fiscal  periods,  to determine  whether the
Fund had met its investment  objective.  The Board members  determined  that the
Fund  had  done  so,  especially  in  light  of  existing  extraordinary  market
conditions,  which include rising  short-term  rates and a relatively flat yield
curve, conditions that reduce hedging benefits. In reaching this conclusion, the
Board members reviewed the Fund's  performance  compared to relevant indices and
funds thought to be generally  comparable to the Fund,  considered the costs and
benefits of the Fund's hedging  strategy in the relevant market  environment and
examined the  differences  between the Fund and certain funds in the  comparison
group,  including the  significant  positions in common  equities of a number of
preferred  stock  funds.  The Board  members  noted the Fund's  adherence to its
respective investment


                                       35



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Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
ADDITIONAL INFORMATION (UNAUDITED) (CONTINUED)
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mandate. The Board members also considered that recent relative underperformance
was  attributable  largely to the Fund's stated hedging  strategies,  which have
been a central aspect of the Fund since inception.

PROFITABILITY

      The Board members considered the Adviser's methodology for determining its
profitability  with respect to the Fund,  and the Adviser's  profit margin on an
after-tax basis  attributable to managing the Fund. The Board members  concluded
that  the   profitability  to  the  Adviser  was  not  excessive  based  on  the
considerable  services it provides to the Fund, the Fund's relative  performance
over time, its success in meeting the Fund's investment objective and the Fund's
relatively  low  expense  ratio  compared  to  funds  with  similar   investment
objectives and  strategies.  The Board members also  considered that the Adviser
provided,  at a lower cost,  services to separate account clients and determined
that the difference was justified in light of the additional  services and costs
associated with managing registered investment companies,  such as the Fund. The
Board members accepted the Adviser's  statement that it did not realize material
indirect  benefits from its  relationship  with the Fund and did not obtain soft
dollar credits from securities trading.

ECONOMIES OF SCALE

      The Board members noted that the Fund, as a closed-end investment company,
was not expected to increase  materially  in size;  thus,  the Adviser would not
benefit from economies of scale. The Board members  considered whether economies
of scale could be realized  because the Adviser  advises  other  similar  funds.
Based on their experience,  the Board members accepted the Adviser's explanation
that  significant  economies  of scale  would  not be  realized  because  of the
complexity  of  managing  preferred  securities  for  separate  funds  and other
portfolios.  Nonetheless,  the Board members noted that the Fund's  advisory fee
schedule declines as assets increase beyond a certain level (commonly known as a
"breakpoint"),  and that breakpoints  provide for a sharing with shareholders of
benefits  derived  as a result of  economies  of scale  arising  from  increased
assets. Accordingly, the Board members determined that the existing advisory fee
levels reflect possible economies of scale.

      In light of their  discussions and  considerations as described above, the
Board members made the following determinations as to the Fund:

      o     the nature and extent and  quality of the  services  provided by the
            Adviser  are  reasonable  and  appropriate  and the  quality  of the
            services is high;

      o     the  Fund's  overall  performance  was  satisfactory,  given  market
            conditions;

      o     the  fee  paid  to  the  Adviser  was  reasonable  in  light  of (i)
            comparative  performance  and expense and advisory fee  information,
            (ii) the cost of the  services  provided and profits to be realized,
            and (iii) the benefits  derived or to be derived by the Adviser from
            the relationship with the Fund; and

      o     there  were not at this time  significant  economies  of scale to be
            realized by the Adviser in managing the Fund's  assets,  and the fee
            was structured to provide for a sharing of the benefits of economies
            of scale.

      Based on these conclusions,  the Board members determined that approval of
the Agreement was in the best interests of the Fund and its shareholders.


                                       36



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DIRECTORS

   Donald F. Crumrine, CFA
      Chairman of the Board
   David Gale
   Morgan Gust
   Karen H. Hogan
   Robert F. Wulf, CFA

OFFICERS

   Donald F. Crumrine, CFA
      Chief Executive Officer
   Robert M. Ettinger, CFA
      President
   R. Eric Chadwick, CFA
      Chief Financial Officer,
      Vice President and Treasurer
   Chad C. Conwell
      Chief Compliance Officer,
      Vice President and Secretary
   Bradford S. Stone
      Vice President and
      Assistant Treasurer
   Christopher D. Ryan, CFA
      Vice President
   Laurie C. Lodolo
      Assistant Compliance Officer,
      Assistant Treasurer and
      Assistant Secretary

INVESTMENT ADVISER

   Flaherty & Crumrine Incorporated
   e-mail: flaherty@pfdincome.com

QUESTIONS  CONCERNING  YOUR  SHARES OF  FLAHERTY  &  CRUMRINE  PREFERRED  INCOME
   OPPORTUNITY FUND?

   o     If your shares are held in a Brokerage Account, contact your Broker.

   o     If you have physical  possession of your shares in certificate form,
         contact the Fund's Transfer Agent & Shareholder Servicing Agent --

                       PFPC Inc.
                       P.O. Box 43027
                       Providence, RI  02940-3027
                       1-800-331-1710

THIS  REPORT IS SENT TO  SHAREHOLDERS  OF FLAHERTY & CRUMRINE  PREFERRED  INCOME
OPPORTUNITY  FUND  INCORPORATED FOR THEIR  INFORMATION.  IT IS NOT A PROSPECTUS,
CIRCULAR OR REPRESENTATION INTENDED FOR USE IN THE PURCHASE OR SALE OF SHARES OF
THE FUND OR OF ANY SECURITIES MENTIONED IN THIS REPORT.



ITEM 2. CODE OF ETHICS.

Not applicable.



ITEM 3. AUDIT COMMITTEE FINANCIAL EXPERT.

Not applicable.



ITEM 4. PRINCIPAL ACCOUNTANT FEES AND SERVICES.

Not applicable.



ITEM 5. AUDIT COMMITTEE OF LISTED REGISTRANTS.

Not applicable.



ITEM 6. SCHEDULE OF INVESTMENTS.

Schedule of Investments in securities of unaffiliated issuers as of the close of
the  reporting  period is included as part of the report to  shareholders  filed
under Item 1 of this form.



ITEM 7.  DISCLOSURE  OF PROXY VOTING  POLICIES  AND  PROCEDURES  FOR  CLOSED-END
MANAGEMENT INVESTMENT COMPANIES.

Not applicable.



ITEM 8. PORTFOLIO MANAGERS OF CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

Not applicable.




ITEM 9.  PURCHASES OF EQUITY  SECURITIES  BY  CLOSED-END  MANAGEMENT  INVESTMENT
COMPANY AND AFFILIATED PURCHASERS.

Not applicable.



ITEM 10. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

There have been no material  changes to the procedures by which the shareholders
may  recommend  nominees to the  registrant's  board of  directors,  where those
changes were  implemented  after the  registrant  last  provided  disclosure  in
response to the  requirements  of Item  7(d)(2)(ii)(G)  of Schedule  14A (17 CFR
240.14a-101), or this Item.


ITEM 11. CONTROLS AND PROCEDURES.

   (a)    The registrant's principal executive and principal financial officers,
          or persons  performing  similar  functions,  have  concluded  that the
          registrant's  disclosure  controls and  procedures (as defined in Rule
          30a-3(c)  under the  Investment  Company Act of 1940,  as amended (the
          "1940 Act") (17 CFR 270.30a-3(c))) are effective,  as of a date within
          90 days of the filing date of the report that includes the  disclosure
          required  by this  paragraph,  based  on  their  evaluation  of  these
          controls and  procedures  required by Rule 30a-3(b) under the 1940 Act
          (17 CFR  270.30a-3(b))  and Rules  13a-15(b)  or  15d-15(b)  under the
          Securities  Exchange Act of 1934, as amended (17 CFR  240.13a-15(b) or
          240.15d-15(b)).


   (b)    There  were no  changes  in the  registrant's  internal  control  over
          financial  reporting (as defined in Rule  30a-3(d)  under the 1940 Act
          (17 CFR  270.30a-3(d))  that occurred during the  registrant's  second
          fiscal  quarter  of  the  period  covered  by  this  report  that  has
          materially affected, or is reasonably likely to materially affect, the
          registrant's internal control over financial reporting.


ITEM 12. EXHIBITS.

   (a)(1) Not applicable.

   (a)(2) Certifications  pursuant  to Rule  30a-2(a)  under  the  1940  Act and
          Section 302 of the Sarbanes-Oxley Act of 2002 are attached hereto.

   (a)(3) Not applicable.

   (b)    Certifications  pursuant  to Rule  30a-2(b)  under  the  1940  Act and
          Section 906 of the Sarbanes-Oxley Act of 2002 are attached hereto.






                                   SIGNATURES

Pursuant to the  requirements  of the  Securities  Exchange  Act of 1934 and the
Investment Company Act of 1940, the registrant has duly caused this report to be
signed on its behalf by the undersigned, thereunto duly authorized.

(registrant) FLAHERTY & CRUMRINE PREFERRED INCOME OPPORTUNITY FUND INCORPORATED

By (Signature and Title)*  /S/ DONALD F. CRUMRINE
                         -------------------------------------------------------
                           Donald F. Crumrine, Director, Chairman of the Board
                           and Chief Executive Officer
                           (principal executive officer)

Date              JULY 17, 2006
    ----------------------------------------------------------------------------


Pursuant to the  requirements  of the  Securities  Exchange  Act of 1934 and the
Investment  Company  Act of  1940,  this  report  has been  signed  below by the
following  persons on behalf of the  registrant and in the capacities and on the
dates indicated.


By (Signature and Title)*  /S/ DONALD F. CRUMRINE
                         -------------------------------------------------------
                           Donald F. Crumrine, Director, Chairman of the Board
                           and Chief Executive Officer
                           (principal executive officer)

Date              JULY 17, 2006
    ----------------------------------------------------------------------------


By (Signature and Title)*  /S/ R. ERIC CHADWICK
                         -------------------------------------------------------
                           R. Eric Chadwick,  Chief Financial  Officer,
                           Treasurer  and  Vice  President
                           (principal financial officer)

Date              JULY 17, 2006
    ----------------------------------------------------------------------------



* Print the name and title of each signing officer under his or her signature.