SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                  SCHEDULE 13G
                                 (Rule 13d-102)

 INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b), (c),
             AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b)
                                (Amendment No. )*







                         Magellan Health Services, Inc.
--------------------------------------------------------------------------------
                                (Name of Issuer)



                                  Common Stock
--------------------------------------------------------------------------------
                         (Title of Class of Securities)



                                    559079207
--------------------------------------------------------------------------------
                                 (CUSIP Number)



                                 January 8, 2004
--------------------------------------------------------------------------------
             (Date of Event which Requires Filing of this Statement)


Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

             [ ]  Rule 13d-1(b)

             [X]  Rule 13d-1(c)

             [ ]  Rule 13d-1(d)



* The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).



                                     Page 1



CUSIP No.         559079207

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       1)      Names of Reporting Person

               S.S. or I.R.S. Identification No. of Above Person

                    Tudor Investment Corporation

                    22-2514825

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       2)      Check the Appropriate Box if a Member of a Group (See
               Instructions)
               (a)

               (b)  X

--------------------------------------------------------------------------------
       3)      SEC Use Only

--------------------------------------------------------------------------------
       4)      Citizenship or Place of Organization           Delaware

--------------------------------------------------------------------------------
Number of Shares       (5)  Sole Voting Power                                  0
Beneficially           ---------------------------------------------------------
Owned by Each          (6)  Shared Voting Power                        2,276,280
Reporting Person       ---------------------------------------------------------
With                   (7)  Sole Dispositive Power                             0
                       ---------------------------------------------------------
                       (8)  Shared Dispositive Power                   2,276,280
--------------------------------------------------------------------------------

                      9)   Aggregate Amount Beneficially Owned by Each
                           Reporting Person         2,276,280
--------------------------------------------------------------------------------

      10)      Check if the Aggregate Amount in Row (9) Excludes Certain Shares
               (See Instructions)

--------------------------------------------------------------------------------
      11)      Percent of Class Represented by Amount in Row 9    6.4%

--------------------------------------------------------------------------------
      12)      Type of Reporting Person (See Instructions)             CO

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                                     Page 2


CUSIP No.         559079207

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       1)      Names of Reporting Person

               S.S. or I.R.S. Identification No. of Above Person

                    Paul Tudor Jones, II

--------------------------------------------------------------------------------
       2)      Check the Appropriate Box if a Member of a Group (See
               Instructions)
               (a)

               (b)  X

--------------------------------------------------------------------------------
       3)      SEC Use Only

--------------------------------------------------------------------------------
       4)      Citizenship or Place of Organization           USA

--------------------------------------------------------------------------------
                       (5)  Sole Voting Power                                  0
Number of Shares       ---------------------------------------------------------
Beneficially           (6)  Shared Voting Power                        2,457,283
Owned by Each          ---------------------------------------------------------
Reporting Person       (7)  Sole Dispositive Power                             0
With                   ---------------------------------------------------------
                       (8)  Shared Dispositive Power                   2,457,283
--------------------------------------------------------------------------------
                       9)  Aggregate Amount Beneficially Owned by Each
                           Reporting Person           2,457,283

--------------------------------------------------------------------------------
      10)      Check if the Aggregate Amount in Row (9) Excludes Certain Shares
               (See Instructions)

--------------------------------------------------------------------------------
      11)      Percent of Class Represented by Amount in Row 9    7.0%

--------------------------------------------------------------------------------
      12)      Type of Reporting Person (See Instructions)             IN

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

                                     Page 3


CUSIP No.         559079207
--------------------------------------------------------------------------------

       1)      Names of Reporting Person

               S.S. or I.R.S. Identification No. of Above Person

                    Tudor Proprietary Trading, L.L.C.

                    13-3720063

--------------------------------------------------------------------------------
       2)      Check the Appropriate Box if a Member of a Group (See
               Instructions)
               (a)

               (b)  X

--------------------------------------------------------------------------------
       3)      SEC Use Only

--------------------------------------------------------------------------------
       4)      Citizenship or Place of Organization           Delaware

--------------------------------------------------------------------------------
                       (5)  Sole Voting Power                                  0
Number of Shares       ---------------------------------------------------------
Beneficially           (6)  Shared Voting Power                          181,003
Owned by Each          ---------------------------------------------------------
Reporting Person       (7)  Sole Dispositive Power                             0
With                   ---------------------------------------------------------
                       (8)  Shared Dispositive Power                     181,003

--------------------------------------------------------------------------------
       9)      Aggregate Amount Beneficially Owned by Each Reporting
               Person                                                    181,003

--------------------------------------------------------------------------------
      10)      Check if the Aggregate Amount in Row (9) Excludes Certain Shares
               (See Instructions)

--------------------------------------------------------------------------------
      11)      Percent of Class Represented by Amount in Row 9              0.5%

--------------------------------------------------------------------------------
      12)      Type of Reporting Person (See Instructions)             OO

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

                                     Page 4


CUSIP No.         559079207

--------------------------------------------------------------------------------
       1)      Names of Reporting Person

               S.S. or I.R.S. Identification No. of Above Person

               The Tudor BVI Global Portfolio Ltd.
--------------------------------------------------------------------------------
       2)      Check the Appropriate Box if a Member of a Group (See
               Instructions)
               (a)

               (b) X

--------------------------------------------------------------------------------
       3)      SEC Use Only

--------------------------------------------------------------------------------
       4)      Citizenship or Place of Organization           Cayman Islands

--------------------------------------------------------------------------------
                       (5)  Sole Voting Power                                  0
Number of Shares       ---------------------------------------------------------
Beneficially           (6)  Shared Voting Power                          332,893
Owned by Each          ---------------------------------------------------------
Reporting Person       (7)  Sole Dispositive Power                             0
With                   ---------------------------------------------------------
                       (8)  Shared Dispositive Power                     332,893

--------------------------------------------------------------------------------
       9)      Aggregate Amount Beneficially Owned by Each Reporting Person
                     332,893

--------------------------------------------------------------------------------
      10)      Check if the Aggregate Amount in Row (9) Excludes Certain Shares
               (See Instructions)

--------------------------------------------------------------------------------
      11)      Percent of Class Represented by Amount in Row 9             0.9%

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

      12)      Type of Reporting Person (See Instructions)             CO

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

                                     Page 5


CUSIP No.         559079207

--------------------------------------------------------------------------------
       1)      Names of Reporting Person

               S.S. or I.R.S. Identification No. of Above Person

               The Altar Rock Fund L.P.

               06-1558414

--------------------------------------------------------------------------------
       2)      Check the Appropriate Box if a Member of a Group (See
               Instructions)
               (a)

               (b)  X

--------------------------------------------------------------------------------
       3)      SEC Use Only

--------------------------------------------------------------------------------
       4)      Citizenship or Place of Organization           Delaware

--------------------------------------------------------------------------------
                       (5)  Sole Voting Power                                  0
Number of Shares       ---------------------------------------------------------
Beneficially           (6)  Shared Voting Power                           10,582
Owned by Each          ---------------------------------------------------------
Reporting Person       (7)  Sole Dispositive Power                             0
With                   ---------------------------------------------------------
                       (8)  Shared Dispositive Power                      10,582

--------------------------------------------------------------------------------
       9)      Aggregate Amount Beneficially Owned by Each Reporting Person
                10,582

--------------------------------------------------------------------------------
      10)      Check if the Aggregate Amount in Row (9) Excludes Certain Shares
               (See Instructions)

--------------------------------------------------------------------------------
      11)      Percent of Class Represented by Amount in Row 9             0.0%

--------------------------------------------------------------------------------
      12)      Type of Reporting Person (See Instructions)             PN

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

                                     Page 6


CUSIP No.         559079207

--------------------------------------------------------------------------------
       1)      Names of Reporting Person

               S.S. or I.R.S. Identification No. of Above Person

                    The Raptor Global Portfolio Ltd.

                    98-0211544

--------------------------------------------------------------------------------
       2)      Check the Appropriate Box if a Member of a Group (See
               Instructions)
               (a)

               (b)  X

--------------------------------------------------------------------------------
       3)      SEC Use Only

--------------------------------------------------------------------------------
       4)      Citizenship or Place of Organization           Cayman Islands

--------------------------------------------------------------------------------
                       (5)  Sole Voting Power                                  0
Number of Shares
Beneficially           (6)  Shared Voting Power                        1,932,805
Owned by Each
Reporting Person       (7)  Sole Dispositive Power                             0
With
                       (8)  Shared Dispositive Power                   1,932,805

--------------------------------------------------------------------------------
       9)      Aggregate Amount Beneficially Owned by Each Reporting
               Person             1,932,805

--------------------------------------------------------------------------------
      10)      Check if the Aggregate Amount in Row (9) Excludes Certain Shares
               (See Instructions)

--------------------------------------------------------------------------------
      11)      Percent of Class Represented by Amount in Row 9              5.5%

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

      12)      Type of Reporting Person (See Instructions)             CO

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

                                     Page 7


Item 1(a).     Name of Issuer:

               Magellan Health Services, Inc

Item 1(b).     Address of Issuer's Principal Executive Offices:

               6950 Columbia Gateway Drive
               Suite 400
               Columbia, Maryland 21046

Item 2(a).     Name of Person Filing:

               Tudor Investment Corporation ("TIC")
               Paul Tudor Jones, II
               The Altar Rock Fund L.P. ("Altar Rock")
               Tudor Proprietary Trading, L.L.C. ("TPT")
               The Tudor BVI Global Portfolio Ltd. ("BVI Portfolio")
               The Raptor Global Portfolio Ltd. ("Raptor Portfolio")

Item 2(b).     Address of Principal Business Office or, if none, Residence:

               The principal business office of each of TIC, Altar Rock, and
               TPT is:

                           1275 King Street
                           Greenwich, CT 06831

               The principal business office of Mr. Jones is:

                           c/o Tudor Investment Corporation
                           1275 King Street
                           Greenwich, CT 06831

               The principal business office of each of Raptor Portfolio and
               BVI Portfolio is:

                           c/o CITCO
                           Kaya Flamboyan 9
                           Curacao, Netherlands Antilles

Item 2(c).     Citizenship:

               TIC is a Delaware corporation.
               Mr. Jones is a citizen of the United States.
               Altar Rock is a Delaware limited partnership.
               TPT is a Delaware limited liability company.
               Raptor Portfolio and BVI Portfolio are companies organized under
                the laws of the Cayman Islands.

Item 2(d).     Title of Class of Securities:

               Common Stock

Item 2(e).     CUSIP Number:

               559079207

                                     Page 8


Item 3.  If this statement is filed pursuant to Rules 13d-1(b), or 13d-2(b),
         check whether the person filing is a:
         (a)   [  ] Broker or Dealer registered under section 15 of the Act
         (b)   [  ] Bank as defined in section 3(a)(6) of the Act
         (c)   [  ] Insurance Company as defined in section 3(a)(19) of the Act
         (d)   [  ] Investment Company registered under section 8 of the
                     Investment Company Act
         (e)   [  ] Investment Adviser registered under section 203 of the
                     Investment Advisers Act of 1940
         (f)   [  ] Employment Benefit Plan, Pension Fund which is subject
                     to the provisions of the Employee Retirement Income
                     Security Act of 1974 or Endowment fund; see section
                     240.13d-1(b)(1)(ii)(F)
         (g)   [  ] Parent Holding Company, in accordance with section
                     240.13d-1(b)(1)(ii)(G) (Note:  See Item 7)
         (h)   [  ] Group, in accordance with section 240.13d-1(b)(1)(ii)(H)

Item 4.  Ownership (As of January 8, 2004).

         (a)   Amount Beneficially Owned:  See Item 9 of cover pages

         (b)   Percent of Class:  See Item 11 of cover pages

         (c)   Number of shares as to which such person has:

               (i)  sole power to vote or to direct the vote
                        See Item 5 of cover pages

              (ii)  shared power to vote or to direct the vote
                        See Item 6 of cover pages

             (iii)  sole power to dispose or to direct the disposition of
                        See Item 7 of cover pages

              (iv)  shared power to dispose or to direct the disposition of
                        See Item 8 of cover pages

               The shares of Common Stock reported herein as beneficially owned
          are owned directly by TPT (181,003 shares), Altar Rock (10,582
          shares), Raptor Portfolio (1,932,805 shares) and BVI Portfolio
          (332,893 shares). Because TIC is the sole general partner of Altar
          Rock and provides investment advisory services to Raptor Portfolio and
          BVI Portfolio, TIC may be deemed to beneficially own the shares of
          Common Stock owned by each of such Reporting Persons. TIC expressly
          disclaims such beneficial ownership. In addition, because Mr. Jones is
          the controlling shareholder of TIC and the indirect controlling equity
          holder of TPT, Mr. Jones may be deemed to beneficially own the shares
          of Common Stock deemed beneficially owned by TIC and TPT. Mr. Jones
          expressly disclaims such beneficial ownership.


Item 5.  Ownership of Five Percent or Less of a Class.

               Not applicable


Item 6.  Ownership of More than Five Percent on Behalf of Another Person.

               Not applicable

Item 7.  Identification and Classification of the Subsidiary Which Acquired the
         Security Being Reported on By the Parent Holding Company.

               Not applicable

Item 8.  Identification and Classification of Members of the Group.

               See cover pages

Item 9.  Notice of Dissolution of Group.

               Not applicable

                                     Page 9


Item 10.  Certification.

          By signing below I certify that, to the best of my knowledge and
belief, the securities referred to above were not acquired and are not held for
the purpose of or with the effect of changing or influencing the control of the
issuer of the securities and were not acquired and are not held in connection
with or as a participant in any transaction having that purpose or effect.

          After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.


                              Dated:       January 9, 2004


                              TUDOR INVESTMENT CORPORATION


                              By: /s/ Stephen N. Waldman
                                  --------------------------------
                                  Stephen N. Waldman
                                  Managing Director and Associate
                                   General Counsel



                                  /s/ Paul Tudor Jones, II
                                  --------------------------------
                                  Paul Tudor Jones, II



                              TUDOR PROPRIETARY TRADING, L.L.C.


                              By: /s/ Stephen N. Waldman
                                  --------------------------------
                                  Stephen N. Waldman
                                  Managing Director and Associate
                                   General Counsel



                              THE TUDOR BVI GLOBAL PORTFOLIO LTD.

                              By: Tudor Investment Corporation,
                                  Trading Advisor

                                  By: /s/ Stephen N. Waldman
                                      ----------------------------
                                      Stephen N. Waldman
                                      Managing Director and Associate
                                       General Counsel


                                    Page 10


                              THE ALTAR ROCK FUND L.P.

                              By: Tudor Investment Corporation,
                                  General Partner


                                  By: /s/ Stephen N. Waldman
                                      ----------------------------
                                      Stephen N. Waldman
                                      Managing Director and Associate
                                       General Counsel



                              THE RAPTOR GLOBAL PORTFOLIO LTD.

                              By: Tudor Investment Corporation,
                                     Investment Adviser




                                   By: /s/ Stephen N. Waldman
                                       ---------------------------
                                       Stephen N. Waldman
                                       Managing Director and Associate
                                        General Counsel


                                    Page 11