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



                                  SCHEDULE 13G

                   UNDER THE SECURITIES EXCHANGE ACT OF 1934
                                (AMENDMENT NO.  )*


                            Infineon Technologies AG
--------------------------------------------------------------------------------
                                (Name of Issuer)

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

                                   D35415-10-4
            --------------------------------------------------------
                                (CUSIP Number)

                               January 12, 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
                                     of 11 Pages



                                     SCHEDULE 13G

CUSIP NO. D35415-10-4                                        Page 2 of 11 Pages


-------------------------------------------------------------------------------
 (1) NAMES OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

     Citigroup Global Markets Limited
-------------------------------------------------------------------------------
 (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

                                                                       (a)  / /
                                                                       (b)  / /
-------------------------------------------------------------------------------
 (3) SEC USE ONLY



-------------------------------------------------------------------------------
 (4) CITIZENSHIP OR PLACE OF ORGANIZATION                      London, England



-------------------------------------------------------------------------------
       NUMBER OF           (5) SOLE VOTING POWER                              0

        SHARES
                           ----------------------------------------------------
     BENEFICIALLY          (6) SHARED VOTING POWER                  29,841,483*

       OWNED BY
                           ----------------------------------------------------
        EACH               (7) SOLE DISPOSITIVE POWER                         0

      REPORTING
                           ----------------------------------------------------
       PERSON              (8) SHARED DISPOSITIVE POWER             29,841,483*

        WITH:
-------------------------------------------------------------------------------
(9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON    29,841,483*

-------------------------------------------------------------------------------
(10) CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
     INSTRUCTIONS)  / /


-------------------------------------------------------------------------------
(11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)                    4.1%*

-------------------------------------------------------------------------------
(12) TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)                             BD



-------------------------------------------------------------------------------
* Assumes conversion/exercise of certain securities held.



                                     SCHEDULE 13G

CUSIP NO. D35415-10-4                                        Page 3 of 11 Pages


-------------------------------------------------------------------------------
 (1) NAMES OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

     Citigroup Global Markets Europe Limited
-------------------------------------------------------------------------------
 (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

                                                                       (a)  / /
                                                                       (b)  / /
-------------------------------------------------------------------------------
 (3) SEC USE ONLY



-------------------------------------------------------------------------------
 (4) CITIZENSHIP OR PLACE OF ORGANIZATION                      London, England



-------------------------------------------------------------------------------
       NUMBER OF           (5) SOLE VOTING POWER                              0

        SHARES
                           ----------------------------------------------------
     BENEFICIALLY          (6) SHARED VOTING POWER                  29,841,483*

       OWNED BY
                           ----------------------------------------------------
        EACH               (7) SOLE DISPOSITIVE POWER                         0

      REPORTING
                           ----------------------------------------------------
       PERSON              (8) SHARED DISPOSITIVE POWER             29,841,483*

        WITH:
-------------------------------------------------------------------------------
(9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON    29,841,483*

-------------------------------------------------------------------------------
(10) CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
     INSTRUCTIONS)  / /


-------------------------------------------------------------------------------
(11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)                    4.1%*

-------------------------------------------------------------------------------
(12) TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)                             HC



-------------------------------------------------------------------------------
* Assumes conversion/exercise of certain securities held.



                                     SCHEDULE 13G

CUSIP NO. D35415-10-4                                        Page 4 of 11 Pages


-------------------------------------------------------------------------------
 (1) NAMES OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

     Citigroup Global Markets International LLC
-------------------------------------------------------------------------------
 (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

                                                                       (a)  / /
                                                                       (b)  / /
-------------------------------------------------------------------------------
 (3) SEC USE ONLY



-------------------------------------------------------------------------------
 (4) CITIZENSHIP OR PLACE OF ORGANIZATION                             Delaware



-------------------------------------------------------------------------------
       NUMBER OF           (5) SOLE VOTING POWER                              0

        SHARES
                           ----------------------------------------------------
     BENEFICIALLY          (6) SHARED VOTING POWER                  29,841,483*

       OWNED BY
                           ----------------------------------------------------
        EACH               (7) SOLE DISPOSITIVE POWER                         0

      REPORTING
                           ----------------------------------------------------
       PERSON              (8) SHARED DISPOSITIVE POWER             29,841,483*

        WITH:
-------------------------------------------------------------------------------
(9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON    29,841,483*

-------------------------------------------------------------------------------
(10) CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
     INSTRUCTIONS)  / /


-------------------------------------------------------------------------------
(11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)                    4.1%*

-------------------------------------------------------------------------------
(12) TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)                            CO


-------------------------------------------------------------------------------
* Assumes conversion/exercise of certain securities held.



                                     SCHEDULE 13G

CUSIP NO. D35415-10-4                                        Page 5 of 11 Pages


-------------------------------------------------------------------------------
 (1) NAMES OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

     Citigroup Financial Products Inc.
     f/k/a "Salomon Brothers Holding Company Inc"
-------------------------------------------------------------------------------
 (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

                                                                       (a)  / /
                                                                       (b)  / /
-------------------------------------------------------------------------------
 (3) SEC USE ONLY



-------------------------------------------------------------------------------
 (4) CITIZENSHIP OR PLACE OF ORGANIZATION                              Delaware



-------------------------------------------------------------------------------
       NUMBER OF           (5) SOLE VOTING POWER                              0

        SHARES
                           ----------------------------------------------------
     BENEFICIALLY          (6) SHARED VOTING POWER                  35,261,707*

       OWNED BY
                           ----------------------------------------------------
        EACH               (7) SOLE DISPOSITIVE POWER                         0

      REPORTING
                           ----------------------------------------------------
       PERSON              (8) SHARED DISPOSITIVE POWER             35,261,707*

        WITH:
-------------------------------------------------------------------------------
(9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON    35,261,707*

-------------------------------------------------------------------------------
(10) CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
     INSTRUCTIONS)  / /


-------------------------------------------------------------------------------
(11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)                    4.9%*

-------------------------------------------------------------------------------
(12) TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)                             CO


-------------------------------------------------------------------------------
* Assumes conversion/exercise of certain securities held.



                                     SCHEDULE 13G

CUSIP NO. D35415-10-4                                        Page 6 of 11 Pages


-------------------------------------------------------------------------------
 (1) NAMES OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

     Citigroup Global Markets Holdings Inc.
     f/k/a "Salomon Smith Barney Holding Inc."
-------------------------------------------------------------------------------
 (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

                                                                       (a)  / /
                                                                       (b)  / /
-------------------------------------------------------------------------------
 (3) SEC USE ONLY



-------------------------------------------------------------------------------
 (4) CITIZENSHIP OR PLACE OF ORGANIZATION                             New York



-------------------------------------------------------------------------------
       NUMBER OF           (5) SOLE VOTING POWER                              0

        SHARES
                           ----------------------------------------------------
     BENEFICIALLY          (6) SHARED VOTING POWER                   35,261,707*

       OWNED BY
                           ----------------------------------------------------
        EACH               (7) SOLE DISPOSITIVE POWER                         0

      REPORTING
                           ----------------------------------------------------
       PERSON              (8) SHARED DISPOSITIVE POWER              35,261,707*

        WITH:
-------------------------------------------------------------------------------
(9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     35,261,707*

-------------------------------------------------------------------------------
(10) CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
     INSTRUCTIONS)  / /


-------------------------------------------------------------------------------
(11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)                    4.9%*

-------------------------------------------------------------------------------
(12) TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)                            HC


-------------------------------------------------------------------------------
* Assumes conversion/exercise of certain securities held.




                                     SCHEDULE 13G

CUSIP NO. D35415-10-4                                        Page 7 of 11 Pages


-------------------------------------------------------------------------------
 (1) NAMES OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

     Citigroup Inc.
-------------------------------------------------------------------------------
 (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

                                                                       (a)  / /
                                                                       (b)  / /
-------------------------------------------------------------------------------
 (3) SEC USE ONLY



-------------------------------------------------------------------------------
 (4) CITIZENSHIP OR PLACE OF ORGANIZATION                             Delaware



-------------------------------------------------------------------------------
       NUMBER OF           (5) SOLE VOTING POWER                              0

        SHARES
                           ----------------------------------------------------
     BENEFICIALLY          (6) SHARED VOTING POWER                  39,123,138*
                                                                             **
       OWNED BY
                           ----------------------------------------------------
        EACH               (7) SOLE DISPOSITIVE POWER                         0

      REPORTING
                           ----------------------------------------------------
       PERSON              (8) SHARED DISPOSITIVE POWER             39,123,138*
                                                                             **
        WITH:
-------------------------------------------------------------------------------
(9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON    39,123,138*
                                                                             **

-------------------------------------------------------------------------------
(10) CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
     INSTRUCTIONS)  / /


-------------------------------------------------------------------------------
(11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)                    5.4%*
                                                                             **

-------------------------------------------------------------------------------
(12) TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)                            HC


-------------------------------------------------------------------------------
*  Assumes conversion/exercise of certain securities held.
** Includes shares held by the other reporting persons.



Item 1(a).     Name of Issuer:

               Infineon Technologies AG

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

               St.-Martin-Strasse 53
               D-81541 Munich
               Federal Republic of Germany

Item 2(a).     Name of Person Filing:

               Citigroup Global Markets Limited ("CGML")
               Citigroup Global Markets Europe Limited ("CGMEL")
               Citigroup Global Markets International LLC ("CGMIL")
               Citigroup Financial Products Inc. ("CFP")
               Citigroup Global Markets Holdings Inc. ("CGM Holdings")
               Citigroup Inc. ("Citigroup")

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

               The address of the principal office of CGML, CGMEL and
               CGMIL is:

               Citigroup Centre, Canada Square
               Canary Wharf, London E14 5LB

               The address of the principal office of both CFP and CGM
               Holdings is:

               388 Greenwich Street
               New York, NY 10013

               The address of the principal office of Citigroup is:

               399 Park Avenue
               New York, NY 10043

Item 2(c).     Citizenship or Place of Organization:

               CGML and CGMEL are chartered in London, England.

               CGM Holdings is chartered in New York.

               CGMIL, CFP and Citigroup are chartered in Delaware.

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

               Ordinary Shares

Item 2(e).     Cusip Number:

               D35415-10-4

                                       Page 8
                                     of 11 Pages


Item 3.      If this Statement is Filed Pursuant to Sections 240.13d-1(b) or
             240.13d-2(b) or (c), Check Whether the Person Filing is a(n):


             (a)  [ ] Broker or dealer registered under section 15 of the
                      Act (15 U.S.C. 78o);

             (b)  [ ] Bank as defined in section 3(a)(6) of the Act
                      (15 U.S.C. 78c);

             (c)  [ ] Insurance company as defined in section 3(a)(19) of
                      the Act (15 U.S.C. 78c);

             (d)  [ ] Investment company registered under Section 8 of the
                      Investment Company Act of 1940 (15 U.S.C. 80a-8);

             (e)  [ ] Investment adviser in accordance with Section
                      240.13d-1(b)(1)(ii)(E);

             (f)  [ ] Employee benefit plan or endowment fund in accordance
                      with Section 240.13d-1(b)(1)(ii)(F);

             (g)  [ ] Parent holding company or control person in accordance
                      with Section  240.13d-1(b)(1)(ii)(G);

             (h)  [ ] Savings association as defined in Section 3(b) of the
                      Federal Deposit Insurance Act (12 U.S.C. 1813);

             (i)  [ ] Church plan that is excluded from the definition of an
                      investment company under Section 3(c)(14) of the
                      Investment Company Act of 1940 (15 U.S.C. 80a-3)

             (j)  [ ] Group, in accordance with Section 240.13d-1(b)(1)(ii)(J).


Item 4.   Ownership.

The Reporting Persons beneficially own the number of shares and the percent of
the class indicated in the table below:



      ----------------------------------------------------------------------------------------------------
                          AS OF JANUARY 12, 2004:     AS OF JANUARY 16, 2004:      AS OF JANUARY 20, 2004:
                          SHARES*     PERCENTAGE*     SHARES*     PERCENTAGE*      SHARES*     PERCENTAGE*
      ----------------------------------------------------------------------------------------------------
                                                                             
       Citigroup        135,108,857     18.6        97,490,187      13.4          39,123,138     5.4
      -----------------------------------------------------------------------------------------------------
       CGM Holdings     131,202,474     18.1        93,334,444      12.8          35,261,707     4.9
      -----------------------------------------------------------------------------------------------------
       CFP              131,202,474     18.1        93,334,444      12.8          35,261,707     4.9
      -----------------------------------------------------------------------------------------------------
       CGMIL            125,782,950     17.3        87,916,120      12.1          29,841,483     4.1
      -----------------------------------------------------------------------------------------------------
       CGMEL            125,782,950     17.3        87,916,120      12.1          29,841,483     4.1
      -----------------------------------------------------------------------------------------------------
       CGML             125,782,950     17.3        87,916,120      12.1          29,841,483     4.1
      -----------------------------------------------------------------------------------------------------


      * INCLUDES SHARES FOR WHICH THE REPORTING PERSONS DISCLAIM BENEFICIAL
        OWNERSHIP.

With respect to the shares set forth in the table above, each Reporting Person
has shared power to vote or direct the vote, and dispose or direct the
disposition of, all of the shares they beneficially own.

                                        Page 9
                                     of 11 Pages


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

          If this statement is being filed to report the fact that as of the
          date hereof the reporting person has ceased to be the beneficial owner
          of more than five percent of the class of securities, check the
          following [ ].

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.

          CGMEL is the sole stockholder of CGML. CGMIL is the majority
          stockholder of CGMEL. CFP owns all of the membership interests
          in CGMIL. CGM Holdings is the sole stockholder of CFP. Citigroup is
          the sole stockholder of CGM Holdings.

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

          Not Applicable.

Item 9.   Notice of Dissolution of Group.

          Not Applicable.




                                       Page 10
                                     of 11 Pages



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.

SIGNATURE.

          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 21, 2004


                      CITIGROUP GLOBAL MARKETS LIMITED


                      By: /s/ Andrew M. Gaulter
                         --------------------------------------------
                         Name:  Andrew M. Gaulter
                         Title:  Secretary




                      CITIGROUP GLOBAL MARKETS EUROPE LIMITED


                      By: /s/ Andrew M. Gaulter
                         --------------------------------------------
                         Name:  Andrew M. Gaulter
                         Title:  Secretary




                      CITIGROUP GLOBAL MARKETS INTERNATIONAL LLC


                      By: /s/ Andrew M. Gaulter
                         --------------------------------------------
                         Name:  Andrew M. Gaulter
                         Title:  Secretary




                      CITIGROUP FINANCIAL PRODUCTS INC.


                      By: /s/ Serena D. Moe
                         --------------------------------------------
                         Name:   Serena D. Moe
                         Title:  Assistant Secretary




                      CITIGROUP GLOBAL MARKETS HOLDINGS INC.


                      By: /s/ Serena D. Moe
                         --------------------------------------------
                         Name:  Serena D. Moe
                         Title:  Assistant Secretary




                       CITIGROUP INC.



                      By: /s/ Serena D. Moe
                         --------------------------------------------
                         Name:  Serena D. Moe
                         Title:  Assistant Secretary



                                Page 11
                              of 11 Pages



                          EXHIBIT INDEX TO SCHEDULE 13G
                          -----------------------------



EXHIBIT 1
---------

Agreement among CGML, CGMEL, CGMIL, CFP, CGM Holdings and Citigroup as to
joint filing of Schedule 13G