<PAGE>   1
    As filed with the Securities and Exchange Commission on           , 2001
                                                            ----------
                                                     Registration No.
                                                                     ----------

                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549
                                   --------

                                   FORM S-8
                            REGISTRATION STATEMENT
                                    UNDER
                          THE SECURITIES ACT OF 1933
                                   --------

                                CITIGROUP INC.
            (Exact Name of Registrant as Specified in Its Charter)

          Delaware                                    52-1568099
(State or Other Jurisdiction                       (I.R.S. Employer
of Incorporation or Organization)                 Identification No.)
                                   --------

           399 Park Avenue                               10043
            New York, NY                               (Zip Code)
(Address of Principal Executive Offices)

                            Citibuilder 401(k) Plan
                      Travelers Group 401(k) Savings Plan

                                Michael A. Ross
                            Deputy General Counsel
                                Citigroup Inc.
                                399 Park Avenue
                              New York, NY 10043
                   (Name and Address of Agent For Service)

                                (212) 559-1000
                      (Telephone Number, Including Area
                         Code, of Agent For Service)


                                  ---------

                       CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
Title Of Securities To       Amount To Be         Proposed Maximum        Proposed Maximum            Amount Of
     Be Registered            Registered         Offering Price Per      Aggregate Offering        Registration Fee
                                                        Share                   Price
---------------------------- ---------------------- ---------------------- ------------------------ --------------------
<S>                          <C>                      <C>                 <C>                       <C>

Common Stock, $.01 par
value per share(1)            20,000,000 shares        $42.675(2)          $ 853,500,000             $213,375.00(2)
---------------------------- ---------------------- ---------------------- ------------------------ --------------------
</TABLE>

(1) In addition, pursuant to Rule 416(c) under the Securities Act of 1933, this
Registration Statement also covers an indeterminate amount of interests to be
offered or sold pursuant to the employee benefit plans described herein.
<PAGE>   2

(2)   The registration fee for the securities registered hereby has been
      calculated pursuant to Rule 457(h) under the Securities Act and is based
      upon the average high and low sale price of the Common Stock as reported
      in the consolidated reporting system on April 4, 2001.


<PAGE>   3

                               EXPLANATORY NOTE

     Citigroup Inc., ("Citigroup"), hereby files this Registration Statement on
Form S-8 relating to 20,000,000 shares of common stock, $.01 par value per
share, of Citigroup ("Common Stock") issuable pursuant to the provisions of the
Citibuilder 401(k) Plan and the Travelers Group 401(k) Savings Plan
(the "Plan").

<PAGE>   4

                                   PART II


              INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Documents by Reference.

The following documents are hereby incorporated by reference in this
Registration Statement:

      (a) The Annual Report on Form 10-K filed by Citigroup Inc. (the
"Registrant") for the fiscal year ended December 31, 2000.

      (b) All other reports filed by Registrant pursuant to Section 13(a) or
15(d) of the Securities Exchange Act of 1934 (the "Exchange Act"), since the
end of the fiscal year covered by the annual report referred to in (a) above.

      (c) The description of the Registrant's Common Stock contained in the
Registrant's Registration Statement filed under the Exchange Act on Form 8-B,
dated May 10, 1988, as updated by the description of the Registrant's Common
Stock contained in the Company's Registration Statement on Form S-3 dated March
21, 2001, and any amendment or report filed for the purpose of further updating
such description.

      All documents subsequently filed by the Registrant pursuant to Section
13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of a
post-effective amendment which indicates that all securities offered hereby
have been sold or which deregisters all securities then remaining unsold,
shall be deemed to be incorporated by reference herein and to be a part hereof
from the date of the filing of such documents.

Item 4.  Description of Securities.

COMMON STOCK

      As of March 1, 2001, Citigroup had outstanding approximately 5.1 billion
shares of common stock. Each holder of common stock is entitled to one vote per
share for the election of directors and for all other matters to be voted on by
Citigroup's stockholders. Except as otherwise provided by law, the holders of
shares of common stock vote as one class together with holders of the shares of
the outstanding Series K Preferred Stock. Holders of common stock may not
cumulate their votes in the election of directors, and are entitled to share
equally in the dividends that may be declared by the board of directors, but
only after payment of dividends required to be paid on outstanding shares of
preferred stock.

      Upon voluntary or involuntary liquidation, dissolution or winding up of
Citigroup, the holders of the common stock share ratably in the assets remaining
after payments to creditors and provision for the preference of any preferred
stock. There are no preemptive or other subscription rights, conversion rights
or redemption or scheduled installment payment provisions relating to shares of
common stock. All of the outstanding shares of common stock are fully paid and
nonassessable. The transfer agent and registrar for the common stock is
Citibank, N.A. The common stock is listed on the New York Stock Exchange and the
Pacific Exchange.

Item 5.  Interests of Named Experts and Counsel.

         Not applicable.

<PAGE>   5

Item 6.  Indemnification of Directors and Officers.

      Subsection (a) of Section 145 of the General Corporation Law of the
State of Delaware (the "DGCL") empowers a corporation to indemnify any person
who was or is a party or is threatened to be made a party to any threatened,
pending or completed action, suit or proceeding, whether civil, criminal,
administrative or investigative (other than an action by or in the right of
the corporation) by reason of the fact that the person is or was a director,
officer, employee or agent of the corporation, or is or was serving at the
request of the corporation as a director, officer, employee or agent of
another corporation, partnership, joint venture, trust or other enterprise,
against expenses (including attorneys' fees), judgments, fines and amounts
paid in settlement actually and reasonably incurred by the person in
connection with such action, suit or proceeding if the person acted in good
faith and in a manner the person reasonably believed to be in or not opposed
to the best interests of the


<PAGE>   6

corporation, and, with respect to any criminal action or proceeding, had no
reasonable cause to believe the person's conduct was unlawful.

      Subsection (b) of Section 145 of the DGCL empowers a corporation to
indemnify any person who was or is a party or is threatened to be made a party
to any threatened, pending or completed action or suit by or in right of the
corporation to procure a judgment in its favor by reason of the fact that such
person acted in any of the capacities set forth above, against expenses
(including attorneys' fees) actually and reasonably incurred by the person in
connection with the defense or settlement of such action or suit if the person
acted in good faith and in a manner he reasonably believed to be in or not
opposed to the best interests of the corporation, except that no
indemnification may be made in respect of any claim, issue or matter as to
which such person shall have been adjudged to be liable to the corporation
unless and only to the extent that the Court of Chancery or the court in which
such action or suit was brought shall determine upon application that, despite
the adjudication of liability but in view of all the circumstances of the
case, such person is fairly and reasonably entitled to indemnity for such
expenses which the Court of Chancery or such other court shall deem proper.

      Section 145 of the DGCL further provides that to the extent a director
or officer of a corporation has been successful on the merits or otherwise in
defense of any action, suit or proceeding referred to in subsections (a) and
(b) of Section 145, or in defense of any claim, issue or matter therein, such
person shall be indemnified against expenses (including attorneys' fees)
actually and reasonably incurred by such person in connection therewith; that
indemnification provided for by Section 145 shall not be deemed exclusive of
any other rights to which the indemnified party may be entitled; that
indemnification provided for by Section 145 shall, unless otherwise provided
when authorized or ratified, continue as to such person who has ceased to be a
director, officer, employee or agent and shall inure to the benefit of such
person's heirs, executors and administrators; and empowers the corporation to
purchase and maintain insurance on behalf of a director or officer of the
corporation against any liability asserted against such person and incurred by
such person in any such capacity, or arising out of such person's status as
such, whether or not the corporation would have the power to indemnify such
person against such liabilities under Section 145. Section Four of Article IV
of the Registrant's By-Laws provides that the Registrant shall indemnify its
directors and officers to the fullest extent permitted by the DGCL.

      The Registrant also provides liability insurance for its directors and
officers which provides for coverage against loss from claims made against
directors and officers in their capacity as such, including, subject to
certain exceptions, liabilities under the federal securities laws.

      Section 102(b)(7) of the DGCL provides that a certificate of
incorporation may contain a provision eliminating or limiting the personal
liability of a director to the corporation or its stockholders for monetary
damages for breach of fiduciary duty as a director provided that such
provision shall not eliminate or limit the liability of a director (i) for any
breach of the director's duty of loyalty to the corporation or its
stockholders, (ii) for acts or omissions not in good faith or which involve
intentional misconduct or a knowing violation of law, (iii) under Section 174
of the DGCL, or (iv) for any transaction from which the director derived an
improper personal benefit. Article TENTH of the Registrant's Restated
Certificate of Incorporation limits the liability of directors to the fullest
extent permitted by Section 102(b)(7).

Item 7.  Exemption from Registration Claimed.

         Not applicable.


<PAGE>   7


Item 8.  Exhibits.

         See Exhibit Index attached hereto.

Item 9.  Undertakings.

      (a) The undersigned registrant hereby undertakes:

      (1) To file, during any period in which offers or sales are being made,
a post-effective amendment to this registration statement:

            (i) To include any  prospectus  required by Section  10(a)(3) of
      the Securities Act of 1933, as amended;

            (ii) To reflect in the prospectus any facts or events arising
      after the effective date of the registration statement (or the most
      recent post-effective amendment thereof) which, individually or in the
      aggregate, represent a fundamental change in the information set forth
      in the registration statement. Notwithstanding the foregoing, any
      increase or decrease in volume of securities offered (if the total
      dollar value of securities offered would not exceed that which was
      registered) and any deviation from the low or high end of the estimated
      maximum offering range may be reflected in the form of prospectus filed
      with the Commission pursuant to Rule 424(b) if, in the aggregate, the
      changes in volume and price represent no more than 20 percent change in
      the maximum aggregate offering price set forth in the "Calculation of
      Registration Fee" table in the effective registration statement;

            (iii) To include any material information with respect to the plan
      of distribution not previously disclosed in the registration statement or
      any material change to such information in the registration statement,
      provided, however, that paragraphs (a)(1)(i) and (a)(l)(ii) do not apply
      if the registration statement is on Form S-3, Form S-8 or Form F-3, and
      the information required to be included in a post-effective amendment by
      those paragraphs is contained in periodic reports filed with or furnished
      to the Securities and Exchange Commission by the registrant pursuant to
      Section 13 or Section 15(d) of the Securities Exchange Act of 1934, as
      amended, that are incorporated by reference in the registration statement.

      (2) That, for the purpose of determining any liability under the
Securities Act of 1933, each such post-effective amendment shall be deemed to
be a new registration statement relating to the securities offered therein,
and the offering of such securities at that time shall be deemed to be the
initial bona fide offering thereof.

      (3) To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination
of the offering.

      (b) The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
registrant's annual report pursuant to Section 13(a) or 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in the
registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such
securities at that time shall be deemed to be the initial bona fide offering
thereof.


<PAGE>   8

      (c) Insofar as indemnification for liabilities arising under the
Securities Act of 1933 may be permitted to directors, officers and controlling
persons of the registrant pursuant to the foregoing provisions, or otherwise,
the registrant has been advised that in the opinion of the Securities and
Exchange Commission such indemnification is against public policy as expressed
in the Act and is, therefore, unenforceable. In the event that a claim for
indemnification against such liabilities (other than the payment by the
registrant of expenses incurred or paid by a director, officer or controlling
person of the registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the registrant will, unless
in the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the Act
and will be governed by the final adjudication of such issue.


<PAGE>   9

                                  SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, as amended,
Citigroup Inc. certifies that it has reasonable grounds to believe that it
meets all of the requirements for filing on Form S-8 and has duly caused this
registration statement or amendment thereto to be signed on its behalf by the
undersigned, thereunto duly authorized, in the City of New York, State of New
York, on April 6, 2001.



                                              CITIGROUP INC.
                                              (Registrant)

                                              By /s/ Todd S. Thompson
                                                 ---------------------
                                                 Todd S. Thompson
                                                 Chief Financial Officer

      Pursuant to the requirements of the Securities Act of 1933, as amended,
this registration statement or amendment thereto has been signed below by the
following persons in the capacities indicated on April 6, 2001.


<TABLE>
<CAPTION>
             Signatures                                  Title
             ----------                                  -----
<S>                                         <C>
                                            Chairman, Chief Executive Officer
         /s/ Sanford I. Weill               (Principal Executive Officer) and
         ----------------------             Director
         Sanford I. Weill


         /s/ Todd S. Thompson               Chief Financial Officer
         ----------------------             (Principal Financial Officer)
         Todd S. Thompson


         /s/ Irwin Ettinger                 Chief Accounting Officer
         ----------------------             (Principal Accounting Officer)
         Irwin Ettinger


         /s/ Roger W. Trupin
         ----------------------             Controller
         Roger W. Trupin                    (Principal Accounting Officer)

                  *
         ----------------------             Director
         C. Michael Armstrong
</TABLE>

<PAGE>   10

<TABLE>
<S>                                         <C>
                  *
         ----------------------             Director
         Alain J. P. Belda


                  *
         ----------------------             Director
         Kenneth J. Bialkin


                  *
         ----------------------             Director
         Kenneth T. Derr


                  *
         ----------------------             Director
         John M. Deutch


                  *
         ----------------------             Director
         Keith W. Hughes

                  *
         ----------------------             Director
         Ann Dibble Jordan

                  *
         ----------------------             Director
         Robert I. Lipp

                  *
         ----------------------             Director
         Reuben Mark


                  *
         ----------------------             Director
         Michael T. Masin


                  *
         ----------------------             Director
         Dudley C. Mecum


                  *
         ----------------------             Director
         Richard D. Parsons


                  *
         ----------------------             Director
         Andrall E. Pearson
</TABLE>

<PAGE>   11

<TABLE>
<S>                                         <C>
                  *
         ----------------------             Director
         Robert E. Rubin


                  *
         ----------------------             Director
         Franklin A. Thomas


                  *
         ----------------------             Director
         Arthur Zankel



*By:   /s/ Todd S. Thomson
       -------------------------
       Todd S. Thomson
       Attorney in Fact
</TABLE>

Pursuant to the requirements of the Securities Act of 1933, as amended, the Plan
has duly caused this Registration Statement to be signed on its behalf by the
undersigned, thereunto duly authorized, in the City of New York, State of New
York, this April 6, 2001.




                                   Citibuilder 401(k) Plan
                                   Travelers Group 401(k) Savings Plan

                                   By: /s/ J. Michael Murray
                                      ----------------------
                                      J. Michael Murray
                                      Vice President, Compensation and Benefits,
                                      Citigroup Inc., the Plan Administrator
<PAGE>   12


                                EXHIBIT INDEX

<TABLE>
<CAPTION>
Exhibit
Number            Description of Document
<S>               <C>
5                 Opinion of Michael A. Ross,
                  with respect to the legality of the securities
                  being registered

23.1              Consent of Michael A. Ross
                  (included in the opinion filed as Exhibit 5)

23.2              Consent of KPMG LLP

24                Powers of Attorney of the directors of the Registrant.
</TABLE>
[{"type": "S-8", "sequence": "1", "filename": "y47292s-8.txt", "description": "CITIGROUP INC.", "secsgml_size_bytes": 21388}]
{"company-data": {"conformed-name": "CITIGROUP INC", "cik": "0000831001", "assigned-sic": "6021", "irs-number": "521568099", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-58452", "film-number": "1597396"}, "business-address": {"street1": "399 PARK AVENUE", "city": "NEW YORK", "state": "NY", "zip": "10043", "phone": "2125591000"}, "mail-address": {"street1": "399 PARK AVENUE", "city": "NEW YORK", "state": "NY", "zip": "10043"}, "former-company": [{"former-conformed-name": "TRAVELERS GROUP INC", "date-changed": "19950519"}, {"former-conformed-name": "TRAVELERS INC", "date-changed": "19940103"}, {"former-conformed-name": "PRIMERICA CORP /NEW/", "date-changed": "19920703"}]}
1
    As filed with the Securities and Exchange Commission on           , 2001
                                                            ----------
                                                     Registration No.
                                                                     ----------

                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549
                                   --------

                                   FORM S-8
                            REGISTRATION STATEMENT
                                    UNDER
                          THE SECURITIES ACT OF 1933
                                   --------

                                CITIGROUP INC.
            (Exact Name of Registrant as Specified in Its Charter)

          Delaware                                    52-1568099
(State or Other Jurisdiction                       (I.R.S. Employer
of Incorporation or Organization)                 Identification No.)
                                   --------

           399 Park Avenue                               10043
            New York, NY                               (Zip Code)
(Address of Principal Executive Offices)

                            Citibuilder 401(k) Plan
                      Travelers Group 401(k) Savings Plan

                                Michael A. Ross
                            Deputy General Counsel
                                Citigroup Inc.
                                399 Park Avenue
                              New York, NY 10043
                   (Name and Address of Agent For Service)

                                (212) 559-1000
                      (Telephone Number, Including Area
                         Code, of Agent For Service)

                                  ---------

                       CALCULATION OF REGISTRATION FEE
Title Of Securities To       Amount To Be         Proposed Maximum        Proposed Maximum            Amount Of
     Be Registered            Registered         Offering Price Per      Aggregate Offering        Registration Fee
                                                        Share                   Price
---------------------------- ---------------------- ---------------------- ------------------------ --------------------
Common Stock, $.01 par
value per share(1)            20,000,000 shares        $42.675(2)          $ 853,500,000             $213,375.00(2)
---------------------------- ---------------------- ---------------------- ------------------------ --------------------
(1) In addition, pursuant to Rule 416(c) under the Securities Act of 1933, this
Registration Statement also covers an indeterminate amount of interests to be
offered or sold pursuant to the employee benefit plans described herein.
2

(2)   The registration fee for the securities registered hereby has been
      calculated pursuant to Rule 457(h) under the Securities Act and is based
      upon the average high and low sale price of the Common Stock as reported
      in the consolidated reporting system on April 4, 2001.
3

                               EXPLANATORY NOTE

     Citigroup Inc., ("Citigroup"), hereby files this Registration Statement on
Form S-8 relating to 20,000,000 shares of common stock, $.01 par value per
share, of Citigroup ("Common Stock") issuable pursuant to the provisions of the
Citibuilder 401(k) Plan and the Travelers Group 401(k) Savings Plan
(the "Plan").
4

                                   PART II

              INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Documents by Reference.

The following documents are hereby incorporated by reference in this
Registration Statement:

      (a) The Annual Report on Form 10-K filed by Citigroup Inc. (the
"Registrant") for the fiscal year ended December 31, 2000.

      (b) All other reports filed by Registrant pursuant to Section 13(a) or
15(d) of the Securities Exchange Act of 1934 (the "Exchange Act"), since the
end of the fiscal year covered by the annual report referred to in (a) above.

      (c) The description of the Registrant's Common Stock contained in the
Registrant's Registration Statement filed under the Exchange Act on Form 8-B,
dated May 10, 1988, as updated by the description of the Registrant's Common
Stock contained in the Company's Registration Statement on Form S-3 dated March
21, 2001, and any amendment or report filed for the purpose of further updating
such description.

      All documents subsequently filed by the Registrant pursuant to Section
13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of a
post-effective amendment which indicates that all securities offered hereby
have been sold or which deregisters all securities then remaining unsold,
shall be deemed to be incorporated by reference herein and to be a part hereof
from the date of the filing of such documents.

Item 4.  Description of Securities.

COMMON STOCK

      As of March 1, 2001, Citigroup had outstanding approximately 5.1 billion
shares of common stock. Each holder of common stock is entitled to one vote per
share for the election of directors and for all other matters to be voted on by
Citigroup's stockholders. Except as otherwise provided by law, the holders of
shares of common stock vote as one class together with holders of the shares of
the outstanding Series K Preferred Stock. Holders of common stock may not
cumulate their votes in the election of directors, and are entitled to share
equally in the dividends that may be declared by the board of directors, but
only after payment of dividends required to be paid on outstanding shares of
preferred stock.

      Upon voluntary or involuntary liquidation, dissolution or winding up of
Citigroup, the holders of the common stock share ratably in the assets remaining
after payments to creditors and provision for the preference of any preferred
stock. There are no preemptive or other subscription rights, conversion rights
or redemption or scheduled installment payment provisions relating to shares of
common stock. All of the outstanding shares of common stock are fully paid and
nonassessable. The transfer agent and registrar for the common stock is
Citibank, N.A. The common stock is listed on the New York Stock Exchange and the
Pacific Exchange.

Item 5.  Interests of Named Experts and Counsel.

         Not applicable.
5

Item 6.  Indemnification of Directors and Officers.

      Subsection (a) of Section 145 of the General Corporation Law of the
State of Delaware (the "DGCL") empowers a corporation to indemnify any person
who was or is a party or is threatened to be made a party to any threatened,
pending or completed action, suit or proceeding, whether civil, criminal,
administrative or investigative (other than an action by or in the right of
the corporation) by reason of the fact that the person is or was a director,
officer, employee or agent of the corporation, or is or was serving at the
request of the corporation as a director, officer, employee or agent of
another corporation, partnership, joint venture, trust or other enterprise,
against expenses (including attorneys' fees), judgments, fines and amounts
paid in settlement actually and reasonably incurred by the person in
connection with such action, suit or proceeding if the person acted in good
faith and in a manner the person reasonably believed to be in or not opposed
to the best interests of the
6

corporation, and, with respect to any criminal action or proceeding, had no
reasonable cause to believe the person's conduct was unlawful.

      Subsection (b) of Section 145 of the DGCL empowers a corporation to
indemnify any person who was or is a party or is threatened to be made a party
to any threatened, pending or completed action or suit by or in right of the
corporation to procure a judgment in its favor by reason of the fact that such
person acted in any of the capacities set forth above, against expenses
(including attorneys' fees) actually and reasonably incurred by the person in
connection with the defense or settlement of such action or suit if the person
acted in good faith and in a manner he reasonably believed to be in or not
opposed to the best interests of the corporation, except that no
indemnification may be made in respect of any claim, issue or matter as to
which such person shall have been adjudged to be liable to the corporation
unless and only to the extent that the Court of Chancery or the court in which
such action or suit was brought shall determine upon application that, despite
the adjudication of liability but in view of all the circumstances of the
case, such person is fairly and reasonably entitled to indemnity for such
expenses which the Court of Chancery or such other court shall deem proper.

      Section 145 of the DGCL further provides that to the extent a director
or officer of a corporation has been successful on the merits or otherwise in
defense of any action, suit or proceeding referred to in subsections (a) and
(b) of Section 145, or in defense of any claim, issue or matter therein, such
person shall be indemnified against expenses (including attorneys' fees)
actually and reasonably incurred by such person in connection therewith; that
indemnification provided for by Section 145 shall not be deemed exclusive of
any other rights to which the indemnified party may be entitled; that
indemnification provided for by Section 145 shall, unless otherwise provided
when authorized or ratified, continue as to such person who has ceased to be a
director, officer, employee or agent and shall inure to the benefit of such
person's heirs, executors and administrators; and empowers the corporation to
purchase and maintain insurance on behalf of a director or officer of the
corporation against any liability asserted against such person and incurred by
such person in any such capacity, or arising out of such person's status as
such, whether or not the corporation would have the power to indemnify such
person against such liabilities under Section 145. Section Four of Article IV
of the Registrant's By-Laws provides that the Registrant shall indemnify its
directors and officers to the fullest extent permitted by the DGCL.

      The Registrant also provides liability insurance for its directors and
officers which provides for coverage against loss from claims made against
directors and officers in their capacity as such, including, subject to
certain exceptions, liabilities under the federal securities laws.

      Section 102(b)(7) of the DGCL provides that a certificate of
incorporation may contain a provision eliminating or limiting the personal
liability of a director to the corporation or its stockholders for monetary
damages for breach of fiduciary duty as a director provided that such
provision shall not eliminate or limit the liability of a director (i) for any
breach of the director's duty of loyalty to the corporation or its
stockholders, (ii) for acts or omissions not in good faith or which involve
intentional misconduct or a knowing violation of law, (iii) under Section 174
of the DGCL, or (iv) for any transaction from which the director derived an
improper personal benefit. Article TENTH of the Registrant's Restated
Certificate of Incorporation limits the liability of directors to the fullest
extent permitted by Section 102(b)(7).

Item 7.  Exemption from Registration Claimed.

         Not applicable.
7

Item 8.  Exhibits.

         See Exhibit Index attached hereto.

Item 9.  Undertakings.

      (a) The undersigned registrant hereby undertakes:

      (1) To file, during any period in which offers or sales are being made,
a post-effective amendment to this registration statement:

            (i) To include any  prospectus  required by Section  10(a)(3) of
      the Securities Act of 1933, as amended;

            (ii) To reflect in the prospectus any facts or events arising
      after the effective date of the registration statement (or the most
      recent post-effective amendment thereof) which, individually or in the
      aggregate, represent a fundamental change in the information set forth
      in the registration statement. Notwithstanding the foregoing, any
      increase or decrease in volume of securities offered (if the total
      dollar value of securities offered would not exceed that which was
      registered) and any deviation from the low or high end of the estimated
      maximum offering range may be reflected in the form of prospectus filed
      with the Commission pursuant to Rule 424(b) if, in the aggregate, the
      changes in volume and price represent no more than 20 percent change in
      the maximum aggregate offering price set forth in the "Calculation of
      Registration Fee" table in the effective registration statement;

            (iii) To include any material information with respect to the plan
      of distribution not previously disclosed in the registration statement or
      any material change to such information in the registration statement,
      provided, however, that paragraphs (a)(1)(i) and (a)(l)(ii) do not apply
      if the registration statement is on Form S-3, Form S-8 or Form F-3, and
      the information required to be included in a post-effective amendment by
      those paragraphs is contained in periodic reports filed with or furnished
      to the Securities and Exchange Commission by the registrant pursuant to
      Section 13 or Section 15(d) of the Securities Exchange Act of 1934, as
      amended, that are incorporated by reference in the registration statement.

      (2) That, for the purpose of determining any liability under the
Securities Act of 1933, each such post-effective amendment shall be deemed to
be a new registration statement relating to the securities offered therein,
and the offering of such securities at that time shall be deemed to be the
initial bona fide offering thereof.

      (3) To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination
of the offering.

      (b) The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
registrant's annual report pursuant to Section 13(a) or 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in the
registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such
securities at that time shall be deemed to be the initial bona fide offering
thereof.
8

      (c) Insofar as indemnification for liabilities arising under the
Securities Act of 1933 may be permitted to directors, officers and controlling
persons of the registrant pursuant to the foregoing provisions, or otherwise,
the registrant has been advised that in the opinion of the Securities and
Exchange Commission such indemnification is against public policy as expressed
in the Act and is, therefore, unenforceable. In the event that a claim for
indemnification against such liabilities (other than the payment by the
registrant of expenses incurred or paid by a director, officer or controlling
person of the registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the registrant will, unless
in the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the Act
and will be governed by the final adjudication of such issue.
9

                                  SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, as amended,
Citigroup Inc. certifies that it has reasonable grounds to believe that it
meets all of the requirements for filing on Form S-8 and has duly caused this
registration statement or amendment thereto to be signed on its behalf by the
undersigned, thereunto duly authorized, in the City of New York, State of New
York, on April 6, 2001.

                                              CITIGROUP INC.
                                              (Registrant)

                                              By /s/ Todd S. Thompson
                                                 ---------------------
                                                 Todd S. Thompson
                                                 Chief Financial Officer

      Pursuant to the requirements of the Securities Act of 1933, as amended,
this registration statement or amendment thereto has been signed below by the
following persons in the capacities indicated on April 6, 2001.
Signatures                                  Title
             ----------                                  -----
Chairman, Chief Executive Officer
         /s/ Sanford I. Weill               (Principal Executive Officer) and
         ----------------------             Director
         Sanford I. Weill

         /s/ Todd S. Thompson               Chief Financial Officer
         ----------------------             (Principal Financial Officer)
         Todd S. Thompson

         /s/ Irwin Ettinger                 Chief Accounting Officer
         ----------------------             (Principal Accounting Officer)
         Irwin Ettinger

         /s/ Roger W. Trupin
         ----------------------             Controller
         Roger W. Trupin                    (Principal Accounting Officer)

                  *
         ----------------------             Director
         C. Michael Armstrong
10
*
         ----------------------             Director
         Alain J. P. Belda

                  *
         ----------------------             Director
         Kenneth J. Bialkin

                  *
         ----------------------             Director
         Kenneth T. Derr

                  *
         ----------------------             Director
         John M. Deutch

                  *
         ----------------------             Director
         Keith W. Hughes

                  *
         ----------------------             Director
         Ann Dibble Jordan

                  *
         ----------------------             Director
         Robert I. Lipp

                  *
         ----------------------             Director
         Reuben Mark

                  *
         ----------------------             Director
         Michael T. Masin

                  *
         ----------------------             Director
         Dudley C. Mecum

                  *
         ----------------------             Director
         Richard D. Parsons

                  *
         ----------------------             Director
         Andrall E. Pearson
11
*
         ----------------------             Director
         Robert E. Rubin

                  *
         ----------------------             Director
         Franklin A. Thomas

                  *
         ----------------------             Director
         Arthur Zankel

*By:   /s/ Todd S. Thomson
       -------------------------
       Todd S. Thomson
       Attorney in Fact
Pursuant to the requirements of the Securities Act of 1933, as amended, the Plan
has duly caused this Registration Statement to be signed on its behalf by the
undersigned, thereunto duly authorized, in the City of New York, State of New
York, this April 6, 2001.

                                   Citibuilder 401(k) Plan
                                   Travelers Group 401(k) Savings Plan

                                   By: /s/ J. Michael Murray
                                      ----------------------
                                      J. Michael Murray
                                      Vice President, Compensation and Benefits,
                                      Citigroup Inc., the Plan Administrator
12

                                EXHIBIT INDEX
Exhibit
Number            Description of Document
5                 Opinion of Michael A. Ross,
                  with respect to the legality of the securities
                  being registered

23.1              Consent of Michael A. Ross
                  (included in the opinion filed as Exhibit 5)

23.2              Consent of KPMG LLP

24                Powers of Attorney of the directors of the Registrant.