<PAGE>
                                                                               .
                                                                               .
                                                                               .
                                                                   EXHIBIT 10.15

<TABLE>

<S>                                                         <C>
$1,500,000                                                    September 30, 2003
(Maximum)                                                   Southfield, Michigan
</TABLE>

                               LINE OF CREDIT NOTE

      N.P. PREMIUM FINANCE COMPANY, a Michigan corporation ("Borrower"), for
value received, promises to pay to the order of NORTH POINTE INSURANCE COMPANY,
a Michigan insurance corporation and any assignee ("Lender") the principal sum
of One Million Five Hundred Thousand Dollars ($1,500,000), or whatever lesser
amount that Lender will have advanced to Borrower under a Line of Credit
Agreement entered into on the same date as this Note ("Line of Credit
Agreement").

      Borrower will repay this principal and all accrued interest to Lender UPON
DEMAND.

      Pending demand, Borrower will make monthly payments of interest on the
principal balance then-outstanding at the per annum rate equal to the so-called
"prime rate of interest" published in the Wall Street Journal. This interest
rate will be adjusted monthly, as of the 10th of each month. During any period
in which the Borrower is in default, the rate will equal four (4) points above
that prime rate of interest.

      Borrower may prepay all or any of the principal balance then due at any
time without prior notice to Lender and without penalty.

      All payments made pursuant to this Note will be applied first against any
payments made by Lender on Borrower's behalf pursuant to the Line of Credit
Agreement, then to accrued interest, and the balance against principal. Borrower
will make its Note payments to Lender wherever Lender designates.

      If Borrower defaults, Lender will be entitled to recover from Borrower, in
addition to the unpaid principal and all accrued interest, an amount equal to
all the costs and expenses Lender actually incurs with the enforcement of this
Note. This will include actual court costs paid, legal, accounting and other
professional fees actually incurred and the like, regardless of whether suit is
brought.

      Lender's waiver or failure to enforce any or its rights and remedies of
Borrower's defaults will not be deemed to constitute a waiver of any prior,
subsequent or contemporaneous default(s) by Borrower.

      Borrower waives demand, protest, presentment for payment, notice of
dishonor, notice of protest, diligence in bringing suit against any party,
resort to collateral and impairment of collateral, and consents that the time
for payment of all or any part of the principal amount, and of the interest on
the principal, may be extended from time to time by
<PAGE>
Lender without notice, and that any such extension will not discharge or
otherwise impair the obligation represented by this Note.

                                        "Borrower"

                                        N.P. PREMIUM FINANCE COMPANY,
                                        a Michigan corporation

                                        By: /s/ John H. Berry
                                            ------------------------------------
                                                John H. Berry
                                                General Manager/Treasurer

Accepted:

"Lender"

NORTH POINTE INSURANCE COMPANY,
a Michigan insurance corporation

By: /s/ B. Matthew Petcoff
    -----------------------------------
        B. Matthew Petcoff
        President

                                        2