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

                                  SCHEDULE 13D

                    Under the Securities Exchange Act of 1934
                               (Amendment No. 1)*

                                    ABB LTD.
                                    --------
                                (Name of Issuer)

                    Registered Shares, CHF 2.50 nominal value
                    -----------------------------------------
                         (Title of Class of Securities)

                                  CH0012221716
                               ------------------
                                 (CUSIP Number)

                               James E. Kaye, Esq.
                       Akin Gump Strauss Hauer & Feld LLP
                               590 Madison Avenue
                            New York, New York 10022
                                 (212) 872-1000
                -------------------------------------------------
                  (Name, Address and Telephone Number of Person
                Authorized to Receive Notices and Communications)

                                  March 4, 2005
                        --------------------------------
                      (Date of Event which Requires Filing
                               of this Statement)

If the filing person has previously  filed a statement on Schedule 13G to report
the  acquisition  that is the subject of this  Schedule  13D, and is filing this
schedule because of ss.ss.240.13d-1(e),  240.13d-1(f) or 240.13d-1(g), check the
following box [ ].

Note:  Schedules  filed in paper format shall include a signed original and five
copies of the schedule,  including all exhibits. See Rule ss.240.13d-7 for other
parties to whom copies are to be sent.

*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
disclosures provided in a prior cover page.

The information required on 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).

                         Continued on following page(s)
                                Page 1 of 8 Pages





                                  SCHEDULE 13D

CUSIP No. CH0012221716                                         Page 2 of 8 Pages


1        Names of Reporting Persons
         I.R.S. Identification Nos. of above persons (entities only)

                  INVESTOR AKTIEBOLAG

2        Check the Appropriate Box If a Member of a Group (See Instructions)
                                             a.  [ ]
                                             b.  [x]

3        SEC Use Only

4        Source of Funds (See Instructions)

                  Not Applicable

5        Check Box If Disclosure of Legal  Proceedings Is Required Pursuant to 
         Items 2(d) or 2(e)

             [  ]

6        Citizenship or Place of Organization

                  Sweden

         Number of       7         Sole Voting Power
           Shares                         187,374,142
        Beneficially
          Owned By       8         Shared Voting Power
            Each                          0
         Reporting
           Person        9         Sole Dispositive Power
            With
                                          187,374,142

                         10        Shared Dispositive Power
                                          0

11       Aggregate Amount Beneficially Owned by Each Reporting Person

                  187,374,142

12       Check Box If the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)

                  [ ]

13       Percent of Class Represented By Amount in Row (11)

                  9.2%

14       Type of Reporting Person (See Instructions)

                  OO





                                                               Page 3 of 8 Pages


                  This  Amendment  No. 1 to Schedule  13D relates to  Registered
Shares,  CHF  2.50  nominal  value  (the  "Shares"),   of  ABB  Ltd,  a  company
incorporated in Switzerland (the "Issuer").  This Amendment No. 1 supplementally
amends the initial  statement  on Schedule  13D,  dated  November  22, 2002 (the
"Initial  Statement").  Investor AB (as defined  below) is filing this Amendment
No. 1 to report that the number of Shares of which  Investor AB may be deemed to
be the beneficial  owner has decreased by more than one percent of the amount of
Shares outstanding. Capitalized terms used but not defined herein shall have the
meanings ascribed to them in the Initial Statement.

Item 2.           Identity and Background.

                  This   Statement   is  being   filed  on  behalf  of  Investor
Aktiebolag,  a limited liability company  incorporated  under the laws of Sweden
("Investor AB," defined as "Buyer" in the Initial Statement).

                  The address of the principal business and the principal office
of  Investor  AB  is  Arsenalgatan  8C,  S-103  32  Stockholm,  Sweden.  Updated
information  concerning  the  identity  and  background  of  the  directors  and
executive  officers  of  Investor  AB is set forth in Annex A  hereto,  which is
incorporated by reference in response to this Item 2.

                  Investor  AB  is  a  Swedish  diversified  industrial  holding
company.  Investor AB's founders and principal  shareholders  are the Wallenberg
foundations,  whose holdings, as of January 31, 2005, represented  approximately
46.9% of the votes and 21.98% of the share capital of Investor AB.

                  During the last five years, neither Investor AB, nor any other
person controlling Investor AB nor, to the best of Investor AB's knowledge,  any
of the persons  listed in Annex A attached  hereto,  (i) has been convicted in a
criminal  proceeding  (excluding traffic violations or similar  misdemeanors) or
(ii) has been a party to a civil proceeding of a judicial or administrative body
of competent  jurisdiction  and as a result of such proceeding was or is subject
to a  judgment,  decree  or final  order  enjoining  future  violations  of,  or
prohibiting or mandating activities subject to, federal or state securities laws
or finding any violation with respect to such laws.

Item 5.           Interest in Securities of the Issuer.

                  (a) The  percentages  set forth herein are  calculated  on the
basis of the Issuer having,  to Investor AB's  knowledge,  2,028,404,505  Shares
outstanding  as of the date  hereof.  Investor AB, for the purpose of Rule 13d-3
promulgated  under the  Securities  Exchange Act of 1934 (the  "Exchange  Act"),
beneficially owns approximately 187,374,142 Shares,  representing  approximately
9.2% of the outstanding Shares of the Issuer.

                  Sune Carlsson, for the purpose of Rule 13d-3 promulgated under
the Exchange Act and to Investor AB's knowledge, beneficially owns approximately
27,185  Shares,  representing  less than 0.1% of the  outstanding  shares of the
Issuer.

                  Bjorn  Svedberg,  for the  purpose of Rule  13d-3  promulgated
under  the  Exchange  Act and to  Investor  AB's  knowledge,  beneficially  owns
approximately  14,892  Shares,  representing  less than 0.1% of the  outstanding
shares of the Issuer.

                  Marcus  Wallenberg,  for the purpose of Rule 13d-3 promulgated
under  the  Exchange  Act and to  Investor  AB's  knowledge,  beneficially  owns
approximately  3,416  Shares,  representing  less than  0.1% of the  outstanding
shares of the Issuer.




                                                               Page 4 of 8 Pages


                  Jacob  Wallenberg,  for the purpose of Rule 13d-3  promulgated
under  the  Exchange  Act and to  Investor  AB's  knowledge,  beneficially  owns
approximately  124,017  Shares,  representing  less than 0.1% of the outstanding
shares of the Issuer.

                  Peter  Wallenberg,  for the purpose of Rule 13d-3  promulgated
under  the  Exchange  Act and to  Investor  AB's  knowledge,  beneficially  owns
approximately  43,494  Shares  representing  less than  0.1% of the  outstanding
shares of the Issuer.

                  Except as set forth in this Item 5(a),  none of  Investor  AB,
and, to its knowledge, any persons named in Annex A hereto beneficially owns any
Shares.

                  (b)  Investor  AB has sole  power to vote  and to  dispose  of
187,374,142 Shares.

                  To  Investor  AB's  knowledge,  each of Sune  Carlsson,  Bjorn
Svedberg,  Marcus  Wallenberg,  Jacob  Wallenberg and Peter  Wallenberg has sole
power to vote and to dispose of his respective Shares.

                  (c)  Except  for the  transactions  listed  on Annex B hereto,
there have been no transactions with respect to the Shares since January 7, 2005
(60 days prior to the date hereof) by Investor AB.

                  (d) Not applicable.

                  (e) Not applicable.





                                                               Page 5 of 8 Pages


                                   SIGNATURES


     After reasonable  inquiry and to the best of my knowledge and belief,  each
of the undersigned certifies that the information set forth in this Statement is
true, complete and correct.

Date:     March 8, 2005                         INVESTOR AB


                                                By: /s/ Adine Grate Axen
                                                    ----------------------------
                                                    Adine Grate Axen
                                                    Managing Director





                                                               Page 6 of 8 Pages


                                     ANNEX A

                 Directors and Executive Officers of Investor AB

     The  name,  business  address,   title,  present  principal  occupation  or
employment of each of the  directors  and executive  officers of Investor AB are
set forth below.  If no business  address is given,  the director's or officer's
business  address  is  Arsenalsgatan  8C,  S-103 32  Stockholm,  Sweden.  Unless
otherwise  indicated,  each occupation set forth opposite an  individual's  name
refers to Investor AB.  Unless  otherwise  indicated  below,  all of the persons
listed below are citizens of Sweden.



                                     

                                              Present Principal Occupation Including Name and
       Name and Business Address                            Address of Employer
--------------------------------------  -----------------------------------------------------

Directors
Claes Dahlback........................  Chairman.
                                        Chairman of EQT, Gambro AB, Stora Enso Oyj and Vin & Sprit
                                        AB. Executive Vice Chairman of W Capital Management AB.

Anders Scharp.........................  Member of the board.
                                        Chairman of  Saab AB, AB SKF and Ph. Nederman & Co. Member
                                        of the Royal Swedish Academy of  Engineering Sciences (IVA).

Hakan Mogren..........................  Member of the board.
                                        Chairman of Affibody AB.
                                        Non-Executive Deputy
                                        Chairman of AstraZeneca
                                        PLC and Deputy Chairman
                                        of Gambro AB. Director of
                                        Group Danone, Norsk Hydro
                                        ASA, Remy Cointreau SA,
                                        The Marianne and Marcus
                                        Wallenberg Foundation and
                                        the Swedish-American
                                        Foundation. Member of the
                                        Royal Swedish Academy of
                                        Engineering Sciences
                                        (IVA).

Sune Carlsson.........................  Member of the board.
                                        Chairman of Atlas Copco AB. Director of Autoliv Inc.,
                                        Picanol NV and Scania AB.

Peter D. Sutherland...................  Member of the board.
                                        Chairman of BP plc and Goldman Sachs International.
                                        Director of the Royal Bank of  Scotland Group Plc.

Bjorn Svedberg........................  Member of the board.
                                        Chairman of Hi3G Access
                                        AB and Nefab AB. Director
                                        of Saab AB and the Knut
                                        and Alice Wallenberg
                                        Foundation. Member of the
                                        Royal Swedish Academy of
                                        Engineering Sciences
                                        (IVA) and the Morgan
                                        Stanley European Advisory
                                        Board.

Marcus Wallenberg.....................  President and Chief Executive Officer.
                                        Vice Chairman of
                                        Ericsson, Saab AB and SEB
                                        Skandinaviska Enskilda
                                        Banken AB. Director of
                                        Astra Zeneca AB, Hi3G
                                        Access AB, Scania AB,
                                        Stora Enso Oyj and the
                                        Knut and Alice Wallenberg
                                        Foundation.






                                                               Page 7 of 8 Pages



                                     

                                              Present Principal Occupation Including Name and
       Name and Business Address                            Address of Employer
--------------------------------------  -----------------------------------------------------

Jacob Wallenberg......................  Vice Chairman.
                                        Chairman of SEB Skandinaviska Enskilda Banken and W Capital
                                        Management. Vice Chairman of Atlas Copco AB,  the Knut and
                                        Alice Wallenberg Foundation and SAS AB. Director of ABB
                                        Ltd., the Confederation of Swedish Enterprise and the Nobel
                                        Foundation.

Sirkka Hamalainen.....................  Member of the Board.
                                        Director of Kone Corporation, HKKK Holding, the Foundation
                                        for Economic Education and SanomaWSOY.

Ulla Litzen...........................  Member of the Board.
                                        Director of Atlas Copco
                                        AB, Karo Bio AB, AB SKF
                                        and Posten AB.

O. Griffith Sexton....................  Member of the Board.


Peter Wallenberg......................  Honorary Chairman.
                                        Chairman of the Knut and
                                        Alice Wallenberg
                                        Foundation and Honorary
                                        Chairman of Atlas Copco
                                        AB.




                                     

                                              Present Principal Occupation Including Name and
       Name and Business Address                            Address of Employer
--------------------------------------  -----------------------------------------------------

Executive Officers
(Who Are Not Directors)
Borje Ekholm..........................  Executive Vice President
Lars Wedenborn........................  Executive Vice President
Henry E. Gooss........................  Managing Director
Adine Grate Axen......................  Managing Director
Fredrik Hillelson.....................  Managing Director






                                                               Page 8 of 8 Pages


                                     ANNEX B


                    RECENT TRANSACTIONS IN THE SECURITIES OF
                                     ABB LTD



                                                                         
                                                                                     Approximate
                          Date of              Nature of          Number of           Price per
For the Account of      Transaction           Transaction           Shares              Share
------------------      -----------           -----------         ----------         -----------

Investor AB               2/24/05           Open Market Sale        300,000           SEK 41.6

Investor AB               2/25/05           Open Market Sale       1,100,000          SEK 41.6

Investor AB               2/25/05           Open Market Sale       1,400,000          SEK 41.7

Investor AB               2/28/05           Open Market Sale       1,750,000          SEK 41.9

Investor AB                3/1/05           Open Market Sale        250,000           SEK 42.1

Investor AB                3/1/05           Open Market Sale        500,000           SEK 42.3

Investor AB                3/2/05           Open Market Sale       3,000,000          SEK 42.5

Investor AB                3/2/05           Open Market Sale       1,000,000          SEK 42.6

Investor AB                3/3/05           Open Market Sale       1,610,000          SEK 42.7

Investor AB                3/3/05           Open Market Sale       3,000,000          SEK 42.5

Investor AB                3/4/05           Open Market Sale       2,825,000          SEK 43.4

Investor AB                3/7/05           Open Market Sale         6,000            SEK 43.3