Exhibit 4.20

                                    GUARANTEE

         For value received, the undersigned hereby, jointly and severally,
unconditionally guarantee, as principal obligor and not only as a surety, to the
Holder of this Security the cash payments in United States dollars of principal
of and interest on this Security in the amounts and at the times when due and
interest on the overdue principal, interest, if any, and Additional Amounts with
respect to this Security, if lawful, and the payment or performance of all other
obligations of the Company under the Indenture (as defined below) or the
Securities, to the Holder of this Security and the Trustee, all in accordance
with and subject to the terms and limitations of this Security, Article XIII of
the Indenture and this Guarantee. This Guarantee will become effective in
accordance with Article XIII of the Indenture and its terms shall be evidenced
therein. The validity and enforceability of any Guarantee shall not be affected
by the fact that it is not affixed to any particular Security.

         Capitalized terms used but not defined herein shall have the meanings
ascribed to them in the Indenture (the "Indenture") dated as of February 27,
2003 among AMVESCAP PLC, the Guarantors and SunTrust Bank, as trustee (the
"Trustee").

         The obligations of the undersigned to the Holders of Securities and to
the Trustee pursuant to this Guarantee and the Indenture are expressly set forth
in Article XIII of the Indenture and reference is hereby made to the Indenture
for the precise terms of the Guarantee and all of the other provisions of the
Indenture to which this Guarantee relates.

         This Guarantee will be a senior unsecured obligation of the Guarantors
and will rank pari passu in right of payment with all other existing and future
senior unsecured obligations of the Guarantors.

         This Guarantee shall be governed by and construed in accordance with
the laws of the state of New York.

         This Guarantee is subject to release upon the terms set forth in the
Indenture.



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         IN WITNESS WHEREOF, the Guarantors have caused this instrument to be
duly executed.

Date: February 27, 2003


                                        A I M MANAGEMENT GROUP INC.


                                        By  /s/  DAWN M. HAWLEY
                                          --------------------------
                                        Name:  Dawn M. Hawley
                                        Title: Senior Vice President and
                                               Chief Financial Officer

                                        A I M ADVISORS, INC.


                                        By  /s/  DAWN M. HAWLEY
                                          --------------------------
                                        Name:  Dawn M. Hawley
                                        Title: Senior Vice President and
                                               Chief Financial Officer

                                        INVESCO INSTITUTIONAL (N.A.), INC.


                                        By  /s/  JOHN D. ROGERS
                                          --------------------------
                                        Name:  John D. Rogers
                                        Title: President & CEO

                                        INVESCO NORTH AMERICAN HOLDINGS, INC.


                                        By  /s/  ERICK R. HOLT
                                          --------------------------
                                        Name:  Erick R. Holt
                                        Title: Secretary