This AMENDMENT, dated as of December 5, 2002 (this "Amendment"), is made to that certain Credit
Agreement, dated as of October 11, 2002, (the "Credit Agreement"), among Alliant Energy Corporation (the
"Borrower"), the lenders party thereto (the "Lenders") and Bank One, NA, as agent (the "Agent").
The Borrower, the Lenders and the Agent previously entered into the Credit Agreement. The Borrower has
requested that the Lenders agree to the amendment to the Credit Agreement as set forth herein, and the Majority
Lenders have agreed to such request, subject to the terms and conditions of this Amendment. Therefore, for
good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the parties agree
SECTION 1. Definitions. Capitalized terms used but not defined herein have the meanings assigned to such terms
in the Credit Agreement.
SECTION 2. Amendment. Section 5.02(a) of the Credit Agreement is amended by (i) deleting the word "and"
from clause (x) of such Section, (ii) replacing the heading "(xi)" in clause (xi) of such Section with the heading
"(xii)" and (iii) inserting the following new clause (xi) immediately following clause (x) of such Section:
(xi) Liens on the capital stock and assets of Whiting Petroleum Corporation ("Whiting") to secure not more than
$230 million aggregate principal amount of Debt of Whiting under a loan agreement to be entered into by Whiting
on or before December 31, 2002; and
SECTION 3. Conditions of Effectiveness. Section 2 of this Amendment shall become effective as of the date first
set forth above when each of the following conditions shall have been fulfilled:
(i) the Majority Lenders and the Borrower shall have executed and delivered to the Agent a counterpart of this
(ii) the Borrower shall have paid (A) to the Agent, for the account of each Lender that shall have executed and
delivered to the Agent a counterpart of this Amendment on o