================================================================================

                                                        ------------------------
                                                              OMB APPROVAL
                                                        ------------------------
                                                        OMB Number: 3235-0515
                                                        ------------------------
                                                        Expires: April 30, 2005
                                                        ------------------------
                                                        Estimated average burden
                                                        hours per response: 43.5
                                                        ------------------------




                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                    -----------------------------------------
                                  SCHEDULE TO/A
            TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1)
                     OF THE SECURITIES EXCHANGE ACT OF 1934
                               (Amendment No. 21)
                              TAUBMAN CENTERS, INC.
                       (Name of Subject Company (Issuer))
                        SIMON PROPERTY ACQUISITIONS, INC.
                           SIMON PROPERTY GROUP, INC.
                             WESTFIELD AMERICA, INC.
                      (Names of Filing Persons (Offerors))
                     COMMON STOCK, PAR VALUE $.01 PER SHARE
                         (Title of Class of Securities)
                                    876664103
                      (CUSIP Number of Class of Securities)

                James M. Barkley, Esq.                  Peter R. Schwartz, Esq.
              Simon Property Group, Inc.                Westfield America Inc.
                 National City Center                  11601 Wilshire Boulevard
              115 West Washington Street                      12th Floor
                    Suite 15 East                        Los Angeles, CA 90025
                Indianapolis, IN 46024                 Telephone: (310) 445-2427
              Telephone: (317) 636-1600
                 (Name, Address and Telephone Numbers of Person
  Authorized to Receive Notices and Communications on Behalf of Filing Persons)
                    -----------------------------------------
                                   Copies to:
  Steven A. Seidman, Esq.                         Scott V. Simpson, Esq.
  Robert B. Stebbins, Esq.              Skadden, Arps, Slate, Meagher & Flom LLP
  Willkie Farr & Gallagher                         One Canada Square
     787 Seventh Avenue                               Canary Wharf
  New York, New York 10019                      London, E14 5DS, England
 Telephone: (212) 728-8000                     Telephone: (44) 20 7519 7000

                    -----------------------------------------
                            CALCULATION OF FILING FEE
================================================================================
        TRANSACTION VALUATION*                       AMOUNT OF FILING FEE**
-------------------------------------------------------------------------------
           $1,243,725,540                                 $248,745.11
===============================================================================
*     Estimated for purposes of calculating the amount of the filing fee only.
      Calculated by multiplying $20.00, the per share tender offer price, by
      62,186,277 shares of Common Stock, consisting of (i) 52,207,756
      outstanding shares of Common Stock, (ii) 2,269 shares of Common Stock
      issuable upon conversion of 31,767,066 outstanding shares of Series B
      Non-Participating Convertible Preferred Stock, (iii) 7,097,979 shares of
      Common Stock issuable upon conversion of outstanding partnership units of
      The Taubman Realty Group, Limited Partnership ("TRG") and (iv) 2,878,273
      shares of Common Stock issuable upon conversion of outstanding options
      (each of which entitles the holder thereof to purchase one partnership
      unit of TRG which, in turn, is convertible into one share of Common
      Stock), based on the Registrant's Preliminary Proxy Statement on Schedule
      14A filed on December 20, 2002, the Registrant's Schedule 14D-9 filed on
      December 11, 2002 and the Registrant's Quarterly Report on Form 10-Q for
      the period ended September 30, 2002.

**    The amount of the filing fee calculated in accordance with Regulation
      240.0-11 of the Securities Exchange Act of 1934, as amended, equals 1/50th
      of one percent of the value of the transaction.


/X/   Check the box if any part of the fee is offset as provided by Rule
      0-11(a)(2) and identify the filing with which the offsetting fee was
      previously paid. Identify the previous filing by registration statement
      number, or the Form or Schedule and the date of its filing.




                                                         

Amount Previously Paid:  $248,745.11                            Filing Party: Simon Property Group, Inc.;
Form or Registration     Schedule TO (File No. 005-42862),                    Simon Property Acquisitions, Inc.;
No.:                     Amendment No. 1 to the Schedule TO and               Westfield America, Inc.
                         Amendment No. 5 to the Schedule TO     Date Filed:   December 5, 2002, December 16, 2002
                                                                              and January 15, 2003


/ / Check the box if the filing relates solely to preliminary communications
made before the commencement of a tender offer.

/ / Check the appropriate boxes below to designate any transactions to which the
statement relates.

    /X/ third-party tender offer subject to Rule 14d-1.

    / / issuer tender offer subject to Rule 13e-4.

    / / going-private transaction subject to Rule 13e-3.

    / / amendment to Schedule 13D under Rule 13d-2.

        Check the following box if the filing is a final amendment reporting the
        results of the tender offer: / /
================================================================================




                                   SCHEDULE TO

         This Amendment No. 21 amends and supplements the Tender Offer Statement
on Schedule TO originally filed with the Securities and Exchange Commission (the
"Commission") on December 5, 2002, as amended and supplemented by Amendment No.
1 thereto filed with the Commission on December 16, 2002, by Amendment No. 2
thereto filed with the Commission on December 27, 2002, by Amendment No. 3
thereto filed with the Commission on December 30, 2002, by Amendment No. 4
thereto filed with the Commission on December 31, 2002, by Amendment No. 5
thereto filed with the Commission on January 15, 2003, by Amendment No. 6
thereto filed with the Commission on January 15, 2003, by Amendment No. 7
thereto filed with the Commission January 16, 2003, by Amendment No. 8 thereto
filed with the Commission on January 22, 2003, by Amendment No. 9 thereto filed
with the Commission on January 23, 2003, by Amendment No. 10 thereto filed with
the Commission on February 7, 2003, by Amendment No. 11 thereto filed with the
Commission on February 11, 2003, by Amendment No. 12 thereto filed with the
Commission on February 18, 2003, by Amendment No. 13 thereto filed with the
Commission on February 21, 2003, by Amendment No. 14 thereto filed with the
Commission on February 21, 2003, by Amendment No. 15 thereto filed with the
Commission on February 27, 2003, by Amendment No. 16 thereto filed with the
Commission on February 27, 2003, by Amendment No. 17 thereto filed with the
Commission on February 28, 2003, by Amendment No. 18 thereto filed with the
Commission on March 3, 2003, by Amendment No. 19 thereto filed with the
Commission on March 6, 2003 and by Amendment No. 20 thereto filed with the
Commission on March 18, 2003 (as amended and supplemented, the "Schedule TO")
relating to the offer by Simon Property Acquisitions, Inc., a Delaware
corporation (the "Purchaser") and wholly owned subsidiary of Simon Property
Group, Inc., a Delaware corporation ("SPG Inc."), to purchase all of the
outstanding shares of common stock, par value $.01 per share (the "Shares"), of
Taubman Centers, Inc. (the "Company") at a purchase price of $20.00 per Share,
net to the seller in cash, without interest thereon, upon the terms and subject
to the conditions set forth in the Offer to Purchase, dated December 5, 2002
(the "Offer to Purchase"), and the Supplement to the Offer to Purchase, dated
January 15, 2003 (the "Supplement"), and in the related revised Letter of
Transmittal (which, together with any supplements or amendments, collectively
constitute the "Offer"). This Amendment No. 21 to the Schedule TO is being filed
on behalf of the Purchaser, SPG Inc. and Westfield America, Inc. ("WEA").

         Capitalized terms used and not defined herein shall have the meanings
assigned to such terms in the Offer to Purchase, the Supplement and the Schedule
TO, as applicable.

         The item numbers and responses thereto below are in accordance with the
requirements of Schedule TO.


Item 6.           PURPOSES OF THE TRANSACTION AND PLANS OR PROPOSALS.

                  On March 21, 2003, SPG Inc., the Purchaser and WEA filed
                  with the Commission a preliminary proxy statement under
                  cover of Schedule 14A pursuant to the Securities Exchange
                  Act of 1934, as the amended (the "Preliminary Solicitation
                  Statement") relating to the solicitation of proxies from
                  the Company's shareholders with respect to the Company's
                  2003 annual meeting. The Preliminary Solicitation
                  Statement is filed herewith as Exhibit (a)(5)(OO).





Item 12.          EXHIBITS.

(a)(5)(OO)        Preliminary Proxy Statement in respect of Taubman Centers,
                  Inc. filed by Simon Property Group, Inc., Simon Property
                  Acquisitions, Inc. and Westfield America, Inc. on March 21,
                  2003.







                                    SIGNATURE

         After due inquiry and to the best of their knowledge and belief, the
undersigned hereby certify as of March 21, 2003 that the information set forth
in this statement is true, complete and correct.


                                    SIMON PROPERTY GROUP, INC.

                                    By:    /s/ JAMES M. BARKLEY
                                         --------------------------------------
                                         Name:  James M. Barkley
                                         Title: Secretary and General Counsel


                                   SIMON PROPERTY ACQUISITIONS, INC.

                                   By:    /s/ JAMES M. BARKLEY
                                         --------------------------------------
                                         Name:  James M. Barkley
                                         Title: Secretary and Treasurer








         After due inquiry and to the best of its knowledge and belief, the
undersigned hereby certifies as of March 21, 2003 that the information set forth
in this statement is true, complete and correct.


                                       WESTFIELD AMERICA, INC.

                                       By: /s/ PETER R. SCHWARTZ
                                           -------------------------------
                                       Name:  Peter R. Schwartz
                                       Title: Senior Executive Vice President






                                  EXHIBIT INDEX


EXHIBIT NO.                                       DESCRIPTION
-----------                                       -----------

(a)(5)(OO)                    Preliminary Proxy Statement in respect of Taubman
                              Centers, Inc. filed by Simon Property Group, Inc.,
                              Simon Property Acquisitions, Inc. and Westfield
                              America, Inc. on March 21, 2003.