FILER: COMPANY DATA: COMPANY CONFORMED NAME: ALLIANT ENERGY CORPORATION CENTRAL INDEX KEY: STANDARD INDUSTRIAL CLASSIFICATION: ELECTRIC AND OTHER SERVICES COMB. [4931] IRS NUMBER: 391380265 STATE OF INCORPORATION: WI FISCAL YEAR END: 12/31 FILING VALUES: FORM TYPE: 35-CERT SEC ACT: SEC FILE NUMBER: 070-10052 FILM NUMBER: BUSINESS ADDRESS: STREET 1: 4902 N Biltmore Lane CITY: MADISON STATE: WI ZIP: 53718 BUSINESS PHONE: 608-458-3311 MAILING ADDRESS STREET 1: P. O. BOX 77007 CITY: MADISON STATE: WI ZIP: 53707 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington D. C. 20549 PUBLIC UTILITY HOLDING COMPANY ACT OF 1935 File No. 70-10052 REPORT PERIOD January 1, 2003 through March 31, 2003 In the Matter of ALLIANT ENERGY CORPORATION, ET AL ALLIANT ENERGY CORPORATION ("AEC") hereby certifies on behalf of itself , Wisconsin Power and Light Company, Interstate Power and Light Company ("IPL"), and Alliant Energy Corporate Services, Inc. "Services") that during the period from January 1, 2003 through March 31, 2003 (the "Reporting Period"): 1(a). Alliant Energy Corporation issued commercial paper as follows: January February March Quarter -------------------------------------------------------------------------------- Begin Balance $ 135,500,000 $ 55,000,000 $ 124,000,000 $ 135,500,000 CP Issued $ 2,283,152,000 $ 1,570,475,000 $ 2,598,000,000 $ 6,451,627,000 CP Matured $ 2,363,652,000 $ 1,501,475,000 $ 2,687,000,000 $ 6,552,127,000 Ending Balance $ 55,000,000 $ 124,000,000 $ 35,000,000 $ 35,000,000 1(b). The weighted average interest rate for the period for all short term debt was as follows: January 1.904% February 2.003% March 2.000% Quarter 1.979% 1(c). Alliant Energy Corporation borrowed from Banks as follows: January February March Quarter -------------------------------------------------------------------------------- Begin Balance $ 85,000,000 $ 259,000,000 $ 168,000,000 $ 85,000,000 CP Issued $ 1,210,000,000 $ 254,000,000 $ 620,000,000 $ 2,084,000,000 CP Matured $(1,036,000,000) $ (345,000,000) $(553,000,000) $(1,934,000,000) Ending Balance $ 259,000,000 $ 168,000,000 $ 235,000,000 $ 235,000,000 1(d). The weighted average interest rate for the period for the bank borrowings was as follows: January 4.545% February 4.620% March 4.522% Quarter 4.529% 2(a). Interstate Power and Light Company issued commercial paper as follows: January February March Quarter -------------------------------------------------------------------------------- Begin Balance $ - $ - $ 18,000,000 $ - CP Issued $ - $ 64,500,000 $ 136,500,000 $ 201,000,000 CP Matured $ - $ 46,500,000 $ 79,000,000 $ 125,500,000 Ending Balance $ - $ 18,000,000 $ 75,500,000 $ 75,500,000 2(b). Weighted Average for the interest rate for the period for short-term debt was as follows: January 0.000% February 1.466% March 1.453% Quarter 1.465% 3(a). For each of the companies participating in the Utility Money Pool during the Reporting Period, the maximum principal amount of short-term borrowings outstanding from the Utility Money Pool, sources other than the Utility Money Pool, and the maximum total short-term borrowings outstanding during the Reporting Period, and the Securities and Exchange Commission ("SEC") borrowing limit for each participant as of the end of the Reporting Period were as follows: Maximum Maximum Other Maximum Money Pool Short-Term Total SEC Company Borrowings Borrowings Borrowings Limit ---------------------------------------------------------------------------- IPL (*) $ 0 $ 75,500,000 $ 475,500,000 $ 250,000,000 WP&L (**) $ 0 $ 73,000,000 $ 73,000,000 $ NA SERVICES (***) $ 119,175,951 $ 0 $ 119,175,951 $ NA (*) IPL ceased borrowing from the Money Pool as of October 11, 2002. (**) All borrowings by WP&L from the Money Pool are exempt under Rule 52(a) and are shown here for information purposes only. WPL ceased borrowings from the Money Pool as of July 25, 2002. (***) Borrowings by Services are exempt under Rule 52(b) and are shown here for information purposes only. 4. During the Reporting Period, the weighted average interest rate for borrowings through the Money Pool was 3.291%. 5. The maximum amount of AEC's short-term borrowings on behalf of itself and the above named participants in the Utility Money Pool during the Reporting Period, and its SEC limit as of the end of the Reporting Period, were as follows: Maximum Maximum Maximum Loans to Corporate Short-Term SEC Money Pool Borrowings Borrowings Limit -------------------------------------------------------------------------------- AEC $ 119,175,951 $ 244,824,049 $ 364,000,000 $ 1,000,000,000 ________________ Said transactions have been carried out in accordance with the terms and conditions of, and for the purpose represented in, the Form U-1 Application-Declaration, as amended, of AEC, et al, in File 70-10052, and in accordance with the terms and conditions of the SEC's order dated June 21,2002, permitting said Application-Declaration to become effective. DATED: May 2, 2003 --------------- ALLIANT ENERGY CORPORATION INTERSTATE POWER AND LIGHT COMPANY ALLIANT ENERGY CORPORATE SERVICES INC. BY: ALLIANT ENERGY CORPORATION BY: /s/ Thomas L. Hanson _________________________________ Thomas L. Hanson Vice President, Treasurer