Exhibit 5.01

                                                   September 5, 2006

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

Ladies and Gentlemen:

      I am the General Counsel, Finance and Capital Markets of Citigroup Inc., a
Delaware corporation (the "Company"). I refer to the filing by the Company with
the Securities and Exchange Commission (the "Commission") of a Post-Effective
Amendment No. 1 to Registration Statement on Form S-3, Reg. No. 333-135163 (as
so amended, the "Registration Statement") relating to junior subordinated debt
securities (the "Junior Subordinated Debt Securities") issued in connection with
the offering by certain affiliated business trusts of the Company of enhanced
capital securities, certain payments in respect of which will be guaranteed by
the Company (the "Guarantees"). The Junior Subordinated Debt Securities being
registered under the Registration Statement will be offered on a continued or
delayed basis pursuant to the provisions of Rule 415 under the Securities Act of
1933, as amended (the "Act").

      Unless otherwise provided in any prospectus forming a part of the
Registration Statement, the Junior Subordinated Debt Securities will be issued
under an Indenture (the "Junior Indenture"), to be entered into between the
Company and JPMorgan Chase Bank, N.A. (the "Junior Trustee"), as Trustee. The
form of Junior Indenture is attached as an exhibit to the Registration
Statement.

      I, or attorneys under my supervision, have examined and are familiar with
originals, or copies certified or otherwise identified to my satisfaction, of
such corporate records of the Company, certificates or documents as I have
deemed appropriate as a basis for the opinions expressed below. In such
examination, I (or such persons) have assumed the legal capacity of all natural
persons, the genuineness of all signatures, the authenticity of all documents
submitted to me (or such persons) as originals, the conformity to original
documents of all documents submitted to me (or such persons) as certified or
photostatic copies and the authenticity of the originals of such copies.

      Based upon and subject to the foregoing and assuming that (i) a Prospectus
and/or term sheet will have been prepared and filed with the Commission
describing the Junior Subordinated Debt Securities offered thereby and will
comply with all applicable laws; (ii) all Junior Subordinated Debt Securities
will be issued and sold in compliance with applicable federal and state laws and
in the manner stated in the Registration Statement and the Prospectus Supplement
and/or term sheet; (iii) the definitive Junior Indenture and a definitive
purchase, underwriting or similar agreement and any other necessary agreement
with respect to the Junior Subordinated Debt Securities offered or issued will
have been duly authorized and validly executed and delivered by the parties
thereto; (iv)

the Junior Subordinated Debt Securities will be sold and delivered at the price
and in accordance with the terms of such agreement and as set forth in the
Registration Statement and the Prospectus or term sheet(s) referred to therein;
and (v) the Company will authorize the offering and issuance of the Junior
Subordinated Debt Securities and the terms and conditions thereof and will take
any other appropriate additional corporate action, I am of the opinion that:

      1. The Company is a duly incorporated and existing corporation under the
laws of the State of Delaware.

      2. Assuming the due authorization, execution, and delivery of the Junior
Indenture by the Junior Trustee, and due execution, authentication and delivery
of the Junior Subordinated Debt Securities in accordance with the terms of the
Junior Indenture, when such Junior Subordinated Debt Securities have been issued
and sold in the manner contemplated by the Registration Statement, such Junior
Subordinated Debt Securities will be legal, valid and binding obligations of the
Company and will be entitled to the benefits of the Junior Indenture.

      Insofar as my opinion relates to the validity, binding effect or
enforceability of any agreement or obligation of the Company, it is subject to
applicable bankruptcy, insolvency, reorganization, fraudulent conveyance,
moratorium or other similar laws affecting creditors' rights generally from time
to time in effect and subject to general principles of equity, regardless of
whether such is considered in a proceeding in equity or at law.

      I note that Section 13.5 of the Junior Indenture provides that, under
certain circumstances, the Company will be obligated to use its commercially
reasonable efforts to sell shares of its common stock and to apply the proceeds
from such sale to pay interest on the Junior Subordinated Debt Securities that
was deferred in accordance with Section 13.1 of the Junior Indenture, and that
the Company shall be deemed not to have used its commercially reasonable efforts
if it determines not to effect such sale solely due to pricing considerations.
Because the General Corporation Law of the State of Delaware reserves to the
Board of Directors the exclusive authority to issue stock and to determine the
price at which such stock is to be issued and, since the Board of Directors has
not yet approved the issuance of such shares of common stock or determined the
per share price thereof, I am not rendering any opinion as to the authorization,
issuance or validity of the common stock issuable pursuant to Section 13.5 of
the Junior Indenture; in addition, for purposes of the opinions set forth below,
I have assumed that the Board of Directors will approve such issuance.

      My opinion is limited to matters governed by the Federal laws of the
United States of America, the laws of the State of New York and the General
Corporation Law of the State of Delaware (including the applicable provisions of
the Delaware Constitution and the reported judicial decisions interpreting the
General Corporation Law of the State of Delaware and such applicable provisions
of the Delaware Constitution). I am not admitted to the practice of law in the
State of Delaware.

      I consent to the use of this opinion in the Registration Statement and to
the reference to my name in the Prospectus constituting a part of such
Registration Statement under the heading "Legal Matters." In giving such
consent, I do not thereby admit that I come within the category of persons whose
consent is required under Section 7 of the Act, or the rules and regulations of
the Securities and Exchange Commission thereunder.

                                        Very truly yours,

                                        /s/ Michael S. Zuckert




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