(As filed January 27, 2004) File No. 70-9891 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 -------------------------------------------------------- POS AMC POST-EFFECTIVE AMENDMENT NO. 4 (Amendment No. 7) to APPLICATION OR DECLARATION ON FORM U-1 UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 1935 --------------------------------------------------------- ALLIANT ENERGY CORPORATION ALLIANT ENERGY RESOURCES, INC. AND ITS SUBSIDIARIES 4902 N. Biltmore Lane Madison, Wisconsin 53718 ALLIANT ENERGY INTEGRATED SERVICES COMPANY AND ITS SUBSIDIARIES ALLIANT ENERGY INVESTMENTS, INC. AND ITS SUBSIDIARIES ALLIANT ENERGY TRANSPORTATION, INC. AND ITS SUBSIDIARIES 200 First Street S.E. Cedar Rapids, Iowa 52401 WHITING PETROLEUM CORPORATION WHITING OIL AND GAS CORPORATION AND ITS SUBSIDIARIES Mile High Center, Suite 2300 1700 Broadway Denver, Colorado 80290-2300 (Names of companies filing this statement and addresses of principal executive offices) ----------------------------------------------------- ALLIANT ENERGY CORPORATION (Name of top registered holding company parent) ----------------------------------------------------- F. J. Buri, Corporate Secretary Alliant Energy Corporation 4902 N. Biltmore Lane Madison, Wisconsin 53718 (Name and address of agent for service) ----------------------------------------------------- The Commission is requested to send copies of all notices, orders and communications in connection with this Application or Declaration to: Barbara J. Swan, General Counsel William T. Baker, Jr., Esq. Alliant Energy Corporation Thelen Reid & Priest LLP 4902 N. Biltmore Lane 875 Third Avenue Madison, Wisconsin 53718 New York, New York 10022 2 Post-Effective Amendment No. 3 (Amendment No. 6) filed in this proceeding on September 18, 2003 is hereby withdrawn. On November 25, 2003, Alliant Energy Corporation ("Alliant Energy"), a registered holding company under the Public Utility Holding Company Act of 1935, as amended (the "Act"), and Alliant Energy Resources, Inc. ("AER"), its wholly-owned non-utility subsidiary, announced that AER had completed the initial public offering ("IPO") of substantially all of the common stock of Whiting Petroleum Corporation ("WPC"), the direct parent of Whiting Oil and Gas Corporation. As a result of the IPO and concurrent issuance of common stock by WPC to certain management employees pursuant to its Phantom Equity Plan, AER now holds only 5.76% of the issued and outstanding shares of common stock of WPC. AER currently intends to divest its remaining interest in WPC, subject to market conditions. Since WPC is no longer a "subsidiary company" of Alliant Energy within the meaning of Section 2(a)(8) of the Act, the relief requested in Post-Effective Amendment No. 3 is no longer required. Alliant Energy will continue to count its proportionate share of WPC's aggregate investment in "energy-related assets" as of the closing date of the IPO, based on AER's percentage ownership of WPC's common stock, against the authorized limit on such investments under the October 3, 2001 order issued in this proceeding. SIGNATURES Pursuant to the requirements of the Public Utility Holding Company Act of 1935, as amended, the undersigned companies have duly caused this Post-Effective Amendment filed herein to be signed on their behalves by the undersigned thereunto duly authorized. ALLIANT ENERGY CORPORATION ALLIANT ENERGY RESOURCES, INC. By: /s/ F. J. Buri ----------- Name: F. J. Buri Title: Corporate Secretary ALLIANT ENERGY INTEGRATED SERVICES COMPANY ALLIANT ENERGY INVESTMENTS, INC. ALLIANT ENERGY TRANSPORTATION, INC. By: /s/ F. J. Buri ----------- Name: F. J. Buri Title: Secretary (signatures continued on next page) WHITING PETROLEUM CORPORATION WHITING OIL AND GAS CORPORATION By: /s/ James J. Volker Name: James J. Volker Title: President and Chief Executive Officer Date: January 27, 2004