SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 _______________________ FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 _______________________ Date of Report (Date of earliest event reported): December 20, 2002 Name of Registrant, State of Incorporation, Address of Principal Commission Executive Offices and IRS Employer File Number Telephone Number Identification Number - ----------- ----------------------------------- --------------------- 1-9894 Alliant Energy Corporation 39-1380265 (a Wisconsin corporation) 4902 N. Biltmore Lane Madison, Wisconsin 53718 Telephone (608) 458-3311 0-4117-1 Interstate Power and Light Company 42-0331370 (an Iowa corporation) Alliant Energy Tower Cedar Rapids, Iowa 52401 Telephone (319) 786-4411 This combined Form 8-K is separately filed by Alliant Energy Corporation and Interstate Power and Light Company. Information contained in this Form 8-K relating to Alliant Energy Corporation and Interstate Power and Light Company is filed by each such registrant on its own behalf. Each of Alliant Energy Corporation and Interstate Power and Light Company makes no representation as to information relating to registrants other than itself. Item 5. Other Events. - ------ ------------ On December 20, 2002, Alliant Energy Corporation (the "Company") issued a press release announcing that its subsidiary, Interstate Power and Light Company ("IP&L"), completed a private placement of $150 million of preferred stock in accordance with Rule 144A under the Securities Act of 1933. Pursuant to Rule 135c of the Securities Act of 1933, the Company is filing a copy of such press release as Exhibit 99.1 hereto, which is incorporated by reference herein. On December 20, 2002, the Company also issued a press release announcing that its subsidiary, Whiting Petroleum Corporation ("Whiting Petroleum"), closed a revolving credit facility with a current maximum borrowing availability of $200 million. The credit facility matures on December 20, 2005. The Company is filing a copy of such press release as Exhibit 99.2 hereto, which is incorporated by reference herein. Item 7. Financial Statements and Exhibits. - ------ --------------------------------- (a) Not applicable. (b) Not applicable. (c) Exhibits. The following exhibits are being filed herewith: (99.1) Alliant Energy Corporation Press Release, dated December 20, 2002, regarding IP&L preferred stock issuance. (99.2) Alliant Energy Corporation Press Release, dated December 20, 2002, regarding Whiting Petroleum credit facility. -2- SIGNATURES ---------- Pursuant to the requirements of the Securities Exchange Act of 1934, each of Alliant Energy Corporation and Interstate Power and Light Company has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. ALLIANT ENERGY CORPORATION Date: December 20, 2002 By: /s/ John E. Kratchmer ------------------------------------ John E. Kratchmer Vice President - Corporate Controller and Chief Accounting Officer INTERSTATE POWER AND LIGHT COMPANY Date: December 20, 2002 By: /s/ John E. Kratchmer ------------------------------------- John E. Kratchmer Vice President - Corporate Controller and Chief Accounting Officer -3- ALLIANT ENERGY CORPORATION INTERSTATE POWER AND LIGHT COMPANY Exhibit Index to Current Report on Form 8-K Dated December 20, 2002 Exhibit Number - ------ (99.1) Alliant Energy Corporation Press Release, dated December 20, 2002, regarding IP&L preferred stock issuance. (99.2) Alliant Energy Corporation Press Release, dated December 20, 2002, regarding Whiting Petroleum credit facility. -4-