UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 ORor 15(d) of ~~The Securities Exchange Act of 1934~~

~~Date~~the ofSecurities ~~Report~~Exchange ~~(Date~~Act of 1934 ~~earliest event reported) February 14, 2013~~

Commission	Name of Registrant, State of Incorporation,	IRS Employer
File Number	Address of Principal Executive Offices and 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
0-337	WISCONSIN POWER AND LIGHT COMPANY	39-0714890
	(a Wisconsin corporation)
	4902 N. Biltmore Lane
	Madison, Wisconsin 53718
	Telephone (608)458-3311

Date of Report (Date of earliest event reported): March 14, 2013

(Former name or former address, if changed since last report.)


Commission File Number	Name of Registrant, State of Incorporation, Address of Principal Executive Offices and Telephone Number	IRS Employer Identification Number

001-04117	Interstate Power and Light Company (an Iowa corporation) Alliant Energy Tower Cedar Rapids, Iowa 52401 Telephone (319) 786-4411	42-0331370

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

~~[ ]~~¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

~~[ ]~~¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

~~[ ]~~¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

~~[ ]~~¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 2 5.~~02 Results~~03 Amendments to Articles of ~~Operations~~Incorporation ~~and~~or ~~Financial~~Bylaws; ~~Condition.~~Change in Fiscal Year

OnUnder ~~February~~the 14restated articles of incorporation, ~~2013~~as amended, ~~Alliant~~of ~~Energy~~Interstate ~~Corporation~~Power and Light Company (~~“Alliant~~the ~~Energy~~“Company”), ~~issued~~the aboard ~~press~~of directors ~~release~~is ~~announcing~~authorized ~~its~~without ~~earnings~~further shareholder action to provide for the ~~fourth~~issuance ~~quarter~~of ~~and~~up ~~year~~to ~~ended~~16,000,000 ~~December~~shares of preferred stock in one or more series. On March 3114, ~~2012~~2013, the Company adopted Articles of Amendment of Interstate Power and Light Company (Regarding Designation and Authorization of 5. A100% ~~copy~~Series D Cumulative Perpetual Preferred Stock) (the “Articles of ~~such~~Amendment”) ~~press~~to ~~release~~its isrestated ~~furnished~~articles of incorporation designating 8,000,000 shares of the Company’s preferred stock as ~~Exhibit~~“5.100% 99Series D Cumulative Perpetual Preferred Stock” (the “Series D Preferred Stock”).1 ~~and~~The isArticles ~~incorporated~~of byAmendment ~~reference~~are ~~herein~~effective as of March 20, 2013.

~~Alliant~~The ~~Energy~~terms ~~included~~of in the ~~press~~Series ~~release~~D ~~2012~~Preferred ~~income~~Stock ~~from~~are ~~continuing~~set ~~operations~~forth ~~and earnings per share from continuing operations excluding charges from non-recurring state income tax impacts and regulatory-related credits from a WPL rate case decision. Alliant Energy included~~ in the ~~press~~Articles release 2011 income from continuing operations and earnings per share from continuing operations excluding impairment charges, net regulatory-related charges from an IPL electric rate case decision, charges related to Alliant Energy’s Cash Balance Pension Plan, charges for emission allowance contracts and benefits from non-recurring state income tax impacts. Alliant Energy believes these non-GAAP financial measures (financial measures not prepared in accordance with accounting principles generally accepted in the United States of ~~America)~~Amendment ~~are useful to investors because they provide an alternate measure to better understand and compare across periods the operating performance of Alliant Energy without the distortion of items~~ that ~~management believes~~ are ~~not~~attached ~~normally~~hereto ~~associated~~as ~~with~~Exhibit ~~ongoing~~3.1 ~~operations,~~ and incorporated ~~also~~herein ~~provide~~by ~~additional information about Alliant Energy’s operations on a basis consistent with the measures that management uses to manage its operations and evaluate its performance~~reference. ~~Alliant~~ ~~Energy’s management also uses income from continuing operations, as adjusted, to determine incentive compensation.~~

~~In addition, Alliant Energy included in the press release 2012 and 2011 Interstate Power and Light Company, Wisconsin Power and Light Company, Alliant Energy Corporate Services, Inc~~Item 8.,01 ~~utility~~Other ~~and~~Events Alliant Energy Corporate Services, Inc., and non-regulated and parent earnings per share from continuing operations. Alliant Energy believes these non-GAAP financial measures are useful to investors because they facilitate an understanding of segment performance and trends and provide additional information about Alliant Energy’s operations on a basis consistent with the measures that management uses to manage its operations and evaluate its performance. Alliant Energy’s management also uses utility and Alliant Energy Corporate Services, Inc. earnings per share from continuing operations to determine incentive compensation.

~~Item~~On 9March 14, 2013, the Company entered into an underwriting agreement (the “Underwriting Agreement”), with Robert W.~~01 Financial~~ ~~Statements~~Baird & Co. Incorporated, Barclays Capital Inc., J.P. Morgan Securities LLC, and ~~Exhibits~~Wells Fargo Securities, LLC, as representatives of the other underwriters named therein, for the sale of 8,000,000 shares (the “Shares”) of the Series D Preferred Stock. The Series D Preferred Stock was offered to the public at a price of $25.00 per share. The underwriting discount was $0.7875 per share for retail orders and $0.5000 per share for institutional orders. The Company estimates that the net proceeds from this offering will be approximately $194.5 million (after deducting underwriting discounts and estimated offering expenses). The Underwriting Agreement is filed as Exhibit 1.1 hereto and is incorporated herein by reference.

~~(a)~~Certain ~~Not~~of ~~applicable~~the underwriters have performed investment banking and advisory services for the Company from time to time for which they have received customary fees and expenses. The underwriters may, from time to time, engage in transactions with and perform services for the Company in the ordinary course of their business.

~~(b)~~On ~~Not~~March 14, ~~applicable~~2013, the Company issued a press release announcing that it had priced the offering of the Shares. The press release is filed as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

~~(c)~~Item 9.01. ~~Not~~Financial ~~applicable~~Statements and Exhibits.

Exhibits are filed herewith in connection with the Registration Statement on Form S-3 (dFile No. 333-178577-02) ~~Exhibits.~~filed ~~The~~by ~~following~~the ~~exhibits~~Company ~~are~~with ~~being~~the ~~furnished~~Securities ~~herewith:~~and Exchange Commission on December 16, 2011.

(~~99.1~~d) ~~Alliant~~ ~~Energy Corporation press release dated February 14, 2013.~~Exhibits


Exhibit No.		Description

1.1		Underwriting Agreement dated March 14, 2013, by and among the Company and Robert W. Baird & Co. Incorporated, Barclays Capital Inc., J.P. Morgan Securities LLC, and Wells Fargo Securities, LLC, as representatives of the other underwriters named therein

3.1		Articles of Amendment of Interstate Power and Light Company (Regarding Designation and Authorization of 5.100% Series D Cumulative Perpetual Preferred Stock)

4.1		Form of Preferred Stock Certificate

5.1		Opinion of Godfrey & Kahn, S.C. as to the legality of the Series D Preferred Stock

99.1		Press Release

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the ~~registrants~~registrant ~~have~~has duly caused this report to be signed on ~~their~~its behalf by the undersigned hereunto duly authorized.

~~ALLIANT~~Dated: ~~ENERGY~~March 20, ~~CORPORATION~~2013

Date: February 14, 2013	By:/s/ Robert J. Durian
	Robert J. Durian
	Controller and Chief Accounting Officer


INTERSTATE POWER AND LIGHT COMPANY

By:		/s/ John E. Kratchmer
		John E. Kratchmer Vice President and Treasurer

~~INTERSTATE~~EXHIBIT ~~POWER~~INDEX ~~AND LIGHT COMPANY~~

Date: February 14, 2013	By:/s/ Robert J. Durian
ExhibitNo.		Description
	Robert J. Durian
1.1		Underwriting Agreement dated March 14, 2013, by and among the Company and Robert W. Baird & Co. Incorporated, Barclays Capital Inc., J.P. Morgan Securities LLC, and Wells Fargo Securities, LLC, as representatives of the other underwriters named therein
	Controller and Chief Accounting Officer
3.1		Articles of Amendment of Interstate Power and Light Company (Regarding Designation and Authorization of 5.100% Series D Cumulative Perpetual Preferred Stock)
4.1		Form of Preferred Stock Certificate
5.1		Opinion of Godfrey & Kahn, S.C. as to the legality of the Series D Preferred Stock
99.1		Press Release

~~WISCONSIN~~4 ~~POWER AND LIGHT COMPANY~~

Date: February 14, 2013	By:/s/ Robert J. Durian
	Robert J. Durian
	Controller and Chief Accounting Officer

ALLIANT ENERGY CORPORATION

INTERSTATE POWER AND LIGHT COMPANY

WISCONSIN POWER AND LIGHT COMPANY

Exhibit Index to Current Report on Form 8-K

Dated February 14, 2013

Exhibit Number

(99.1) Alliant Energy Corporation press release dated February 14, 2013.

Filing Compare · INTERSTATE POWER & LIGHT CO