Exhibit 99.1


             [Skadden, Arps, Slate, Meagher and Flom LLP letterhead]


                                                     September 27, 2004

Citigroup Inc.
399 Park Avenue
New York, New York 10043

Citigroup Capital XI
399 Park Avenue
New York, New York 10043

                  Re:  Registration Statement on Form S-3
                       Registration No. 333-117615
                       ---------------------------

Ladies and Gentlemen:

     We have acted as counsel to Citigroup Inc., a Delaware corporation (the
"Company"), and Citigroup Capital XI, a statutory trust formed under the laws of
the state of Delaware (the "Trust"), in connection with the above-captioned
registration statement on Form S-3 filed with the Securities and Exchange
Commission (the "Commission") on July 23, 2004, as amended by Amendment No. 1
thereto filed with the Commission on August 31, 2004 (such registration
statement, as so amended, the "Registration Statement") for the purpose of
registering (i) Capital Securities representing undivided beneficial interests
in the assets of the Trust and (ii) Junior Subordinated Debt Securities issued
by the Company to the Trust, in connection with the sale of the Capital
Securities.

     This opinion is being provided to you in accordance with the requirements
of Item 601(b)(8) of Regulation S-K under the Securities Act of 1933.

     In rendering our opinion set forth below, we have reviewed the Registration
Statement, the prospectus thereunder dated September 14, 2004 (the "Prospectus")
and such other materials as we have deemed necessary or appropriate as a basis
for our opinion. In addition, we have considered the current provisions of the
Internal Revenue Code of 1986, as amended (the "Code"), Treasury regulations
promulgated thereunder, judicial decisions and Internal Revenue Service
("Service") rulings, all of which are subject to change, possibly with
retroactive effect. A change in the authorities upon which our opinion is based
could affect our conclusions. There can


Citigroup Inc.
Citigroup Capital XI
September 27, 2004
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be no assurances, moreover, that the opinion expressed herein will be accepted
by the Service or, if challenged, by a court.

     Based solely upon and subject to the foregoing, we are of the opinion that,
although the discussion set forth in the Prospectus under the heading "UNITED
STATES FEDERAL INCOME TAX CONSIDERATIONS" does not purport to discuss all
possible United States federal income tax consequences of the purchase,
ownership and disposition of the Capital Securities to an initial holder of the
Capital Securities, such discussion constitutes, in all material respects, a
fair and accurate summary of the United States federal income tax consequences
of the purchase, ownership and disposition of the Capital Securities to such
holder.

     Except as set forth above, we express no opinion to any party as to the tax
consequences, whether federal, state, local or foreign, of the issuance of the
Capital Securities, the Junior Subordinated Debt Securities or of any
transaction related to or contemplated by such issuance. We disclaim any
undertaking to advise you of any subsequent changes of the facts stated or
assumed herein or any subsequent changes in applicable law. We hereby consent to
the use of our name under the heading "Legal Matters" in the Prospectus and the
filing of this opinion with the Commission as Exhibit 8.1 to the Registration
Statement. In giving this consent, we do not thereby admit that we are within
the category of persons whose consent is required under Section 7 of the
Securities Act of 1933, as amended, or the rules and regulations of the
Commission promulgated thereunder.

                                   Very truly yours,

                                  /s/ Skadden, Arps, Slate, Meagher and Flom LLP