<PAGE>

                                                                   EXHIBIT 10.21

                            REVOLVING LOAN AGREEMENT

         THIS AGREEMENT, having an effective date of July 31, 2002, is made by
and between THE ST. PAUL COMPANIES, INC., a Minnesota corporation, (the
"LENDER") and THE JOHN NUVEEN COMPANY, a Delaware corporation, (the "BORROWER").

         WHEREAS, BORROWER is 78% owned by LENDER and its wholly owned
subsidiary ST. PAUL FIRE AND MARINE INSURANCE COMPANY; and

         WHEREAS, LENDER intends to loan money to BORROWER from time to time for
working capital and other purposes; and

         WHEREAS, BORROWER seeks to borrow money from LENDER on the terms and
conditions set forth herein.

         NOW, THEREFORE, in consideration of these premises and of other good
and valuable consideration, the parties hereto agree as follows:

         1. LENDER will loan to BORROWER, at LENDER's option, an aggregate
principal amount that shall not exceed Two Hundred Fifty Million United States
Dollars ($250,000,000.00) (the "Loan Limit"). The aggregate principal amount
shall be calculated by adding the sum of all outstanding advances (the
"Loan(s)") to BORROWER hereunder.

         2. If there is no balance outstanding at the time of any Loan under
this Agreement, such Loan shall bear interest from the date of such Loan until
the first business day of the following month at a floating rate equal to the
one month USD LIBOR as set by the British Bankers Association (Bloomberg US0001M
Index) on the date of the first Loan plus the applicable margin as set out in
the table below:

<TABLE>
<CAPTION>

                       Public Short Term Debt Rating                                Applicable Margin for
                    S&P/Moody's/Fitch ("Rating Agencies")                                USD Advances
<S>                                                                                 <C>
        Level 1 (a) (b)
               A1/P1/F1                                                                      +0.00%
        Level 2 (a) (b)
               A2/P2/F2                                                                      +0.25%
        (a)       If LENDER's Short Term Debt Rating by any 2 Rating Agencies
                  equals A1/P1/F1 then the Level 1 margin shall apply else the
                  Level 2 margin shall apply.
        (b)       If LENDER's short term debt ratings by any 2 Rating Agencies
                  are A1/P1/F1 and are under review by any 2 Rating Agencies
                  then the Level 2 margin shall apply. Under review means on
                  CreditWatch by S&P, under Review by Moody's or on Rating Watch
                  by Fitch.
</TABLE>


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On the first business day of each calendar month thereafter, the interest
rate shall be reset to equal the one month USD LIBOR plus the applicable margin
as set by the British Bankers Association (Bloomberg US0001M Index) as of the
first business day of such calendar month. This reset interest rate shall apply
to all then outstanding Loan(s), and to any additional Loan(s) made during the
calendar month, until the first business day of the following month. Interest on
outstanding Loan(s) shall accrue and compound monthly and shall be paid
quarterly on each January 15, April 15, July 15, and October 15. Principal and
accrued interest shall be paid upon prepayment of Loan(s), at maturity, or upon
termination.

         3. BORROWER promises to repay on July 15, 2003, all Loan(s) made by
LENDER to BORROWER pursuant to this Agreement, together with all accrued and
unpaid interest thereon, as evidenced by the books and records of LENDER, which
shall be presumptive evidence of the amount of Loan(s) outstanding.
Notwithstanding the foregoing, BORROWER may prepay the outstanding Loan(s) and
accrued interest at any time.

         4. Amounts borrowed and repaid may be reborrowed, so long as the
aggregate Loan amount outstanding does not exceed the Loan Limit.

         5. The obligation of BORROWER to repay the Loan(s) pursuant to this
Agreement shall be evidenced by a ledger, kept by LENDER, and LENDER shall
record the advance of funds respecting the Loan(s) to BORROWER as well as all
repayments made on the Loan(s) by BORROWER in the form attached hereto as
Exhibit A ("Revolving Loan Agreement Record of Loan(s) and Repayment(s)").
LENDER's calculation of amounts due it by BORROWER pursuant to this clause and
in accordance with this Agreement shall be presumptive evidence thereof, absent
manifest error. The calculation of interest due at maturity shall be recorded in
the form attached hereto as Exhibit B ("Revolving Loan Agreement Record of
Interest Amount(s) Due and Maturity Date(s)").

         6. This Agreement may be terminated by either party upon thirty (30)
days' written notice to the other party. Such written notice shall be sent via
registered mail to the address for notices provided in clause 10 below and shall
be deemed received by the other party upon the date on which the mail was
delivered as evidenced by the signature on the registered mail receipt. In the
event of termination, all Loan(s) made by LENDER to BORROWER pursuant to this
Agreement, and all accrued and unpaid interest, shall immediately become due and
payable upon demand by LENDER.

         7. In the event of non-payment by BORROWER, all Loan(s) made by LENDER
to BORROWER pursuant to this Agreement, and all accrued and unpaid interest,
shall immediately become due and payable upon demand by LENDER.

         8. Notwithstanding any provision of this Agreement to the contrary,
LENDER may at any time determine not to advance Loan(s) as requested by BORROWER
hereunder, and LENDER shall not be obligated to make any such Loan(s).

         9. Loan requests received by 8:00 a.m. Central Standard Time will
be funded the same business day. Loan requests should be submitted in writing
to: Mr. Chris Gies with a copy



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to Mr. Joel Campbell and Ms. Sheila M. Colgan.  Loan requests may be submitted
via e-mail or via facsimile as follows:


<TABLE>
<CAPTION>

              Name                          E-mail                       Facsimile                  Phone
              ----                          ------                       ---------                  -----
<S>      <C>                        <C>                                <C>                       <C>
         Mr. Chris Gies             chris.gies@stpaul.com              (651) 310-7404            (651) 310-3479
         Mr. Joel Campbell          joel.campbell@stpaul.com           (651) 310-7404            (651) 310-6883
         Ms. Sheila Colgan          sheila.colgan@stpaul.com           (651) 310-3386            (651) 310-7441

</TABLE>

         10.  Notices to LENDER shall be addressed to:
              Mr. Paul McDonough
              Vice President & Treasurer
              The St. Paul Companies, Inc.
              385 Washington Street
              St. Paul, Minnesota 55102
              Phone: (651) 310-2866
              Fax:     (651) 310-3386

              Notices to BORROWER shall be addressed to:
              Mr. Peter H. D'Arrigo
              Vice President & Treasurer
              The John Nuveen Company
              333 West Wacker Drive
              Chicago, Illinois 60606
              Phone: (312) 917-8282
              Fax:     (312) 917-8049

         11.  This Agreement shall be governed by and construed in accordance
with Minnesota law.

         12.  This Agreement is effective as of the date first set forth above,
and shall not be amended or modified except in writing signed by an authorized
representative of each of the parties hereto.

         IN WITNESS WHEREOF, the undersigned have caused this Agreement to be
executed as of this 29th day of July 2002.

WITNESSED BY:                           THE ST. PAUL COMPANIES, INC.

/s/ Paul McDonough                      By:      /s/ Thomas A. Bradley
--------------------------                       ------------------------------
                                        Name:    Thomas A. Bradley
                                        Title:   Chief Financial Officer

WITNESSED BY:                           THE JOHN NUVEEN COMPANY

/s/ Peter H. D'Arrigo                   By:      /s/ Margaret E. Wilson
--------------------------                       ------------------------------
                                        Name:    Margaret E. Wilson
                                        Title:   Senior Vice President, Finance


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