Exhibit 4.05

CERTIFICATE OF TRUST

OF

CITIGROUP CAPITAL XXI

     This Certificate of Trust is being executed as of April 20, 2007 for the purposes of organizing a statutory trust pursuant to the Delaware Statutory Trust Act, 12 Del. C. §3801 et seq. (the “Act”).

     The undersigned, the trustees of Citigroup Capital XXI, hereby certify as follows:

     1. Name. The name of the statutory trust being formed hereby is “Citigroup Capital XXI” (the “Trust”).

     2. Delaware Trustee. The name and business address of the trustee of the Trust which has its principal place of business in the State of Delaware are as follows:

The Bank of New York (Delaware)
100 White Clay Center
Route 273
P. O. Box 6995
Newark, DE 19711

     3. Effective. This Certificate of Trust shall be effective immediately upon filing in the Office of the Secretary of State of the State of Delaware.

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Dated: April 20, 2007

By:	/s/ John Gerspach
John Gerspach, as Regular Trustee
By:	/s/ Eric L. Wentzel
Eric L. Wentzel, as Regular Trustee
By:	/s/ Saul Rosen
Saul Rosen, as Regular Trustee
THE BANK OF NEW YORK (DELAWARE), as Delaware Trustee
By:	/s/ Kristine K. Gullo
Name: Kristine K. Gullo Title: Vice President
CITIGROUP INC., as Sponsor
By:	/s/ Gary Crittenden
Name: Gary Crittenden Title: Chief Financial Officer

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