Obbligazione Interstate Energy & Lighting 6.25% ( US461070AG92 ) in USD

Interstate Energy & Lighting

100 USD ▼

Stati Uniti

US461070AG92 ( in USD )

6.25% per anno ( pagato 2 volte l'anno)

15/07/2039

Prospetto opuscolo dell'obbligazione Interstate Power and Light US461070AG92 en USD 6.25%, scadenza 15/07/2039

1 000 USD

300 000 000 USD

461070AG9

A- ( Upper medium grade - Investment-grade )

Baa1 ( Lower medium grade - Investment-grade )

15/01/2026 ( In 160 giorni )

Interstate Power and Light era una società di servizi pubblici statunitense, con sede a Kansas City, Missouri, che operava principalmente nell'Iowa e nel Missouri, fornendo energia elettrica e gas naturale.

The Obbligazione issued by Interstate Energy & Lighting ( United States ) , in USD, with the ISIN code US461070AG92, pays a coupon of 6.25% per year.
The coupons are paid 2 times per year and the Obbligazione maturity is 15/07/2039

The Obbligazione issued by Interstate Energy & Lighting ( United States ) , in USD, with the ISIN code US461070AG92, was rated Baa1 ( Lower medium grade - Investment-grade ) by Moody's credit rating agency.

The Obbligazione issued by Interstate Energy & Lighting ( United States ) , in USD, with the ISIN code US461070AG92, was rated A- ( Upper medium grade - Investment-grade ) by Standard & Poor's ( S&P ) credit rating agency.

Final Prospectus Supplement
424B5 1 d424b5.htm FINAL PROSPECTUS SUPPLEMENT
Table of Contents
Filed Pursuant to Rule 424(b)5
Registration No. 333-159478

Prospectus Supplement
(To Prospectus dated June 5, 2009)
$300,000,000
Interstate Power and Light Company
6.25% Senior Debentures due 2039
We will pay interest on the senior debentures on January 15 and July 15 of each year, beginning on January 15,
2010. The senior debentures will mature on July 15, 2039. We may redeem some or all of the senior debentures
at any time and from time to time at the redemption prices described in this prospectus supplement.
The senior debentures will be our unsecured senior obligations and rank equally with our other unsecured senior
indebtedness from time to time outstanding. The senior debentures will be issued only in registered form in
denominations of $1,000, and will not be listed on any securities exchange.
Investing in the senior debentures involves risks. See "Risk Factors" beginning on page 20 of our Annual
Report on Form 10-K for the year ending December 31, 2008.

Per Senior

Debenture
Total
Public offering price(1)

99.368%
$298,104,000
Underwriting discount

0.875%
$
2,625,000
Proceeds, before expenses, to Interstate Power and Light Company(1)

98.493%
$295,479,000

(1) Plus accrued interest if any, from July 10, 2009, if settlement occurs after that date.
Neither the Securities and Exchange Commission nor any state securities commission has approved or
disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is
truthful or complete. Any representation to the contrary is a criminal offense.
The senior debentures will be ready for delivery in book-entry form only through The Depository Trust Company
on or about July 10, 2009.

Joint Book-Running Managers

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Final Prospectus Supplement
Banc of America Securities LLC

Wells Fargo Securities

Mitsubishi UFJ Securities

RBS

Co-Managers

Commerzbank Corporates & Markets

Mizuho Securities USA Inc.
The date of this prospectus supplement is July 7, 2009
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Final Prospectus Supplement
Table of Contents
TABLE OF CONTENTS
Prospectus Supplement

Page
About This Prospectus Supplement

ii
Forward-Looking Statements

iii
Prospectus Supplement Summary
S- 1
Use of Proceeds

S-4
Capitalization

S-4
The Company

S-5
Description of Senior Debentures

S-8
Underwriting
S-12
Legal Matters
S-14
Experts
S-14
Prospectus

Page
About This Prospectus

2
Interstate Power and Light Company

3
Use of Proceeds

3
Ratio of Earnings to Fixed Charges and Ratio of Earnings to Combined Fixed Charges and Preferred
Dividend Requirements

3
Description of Preferred Stock

4
Description of Debt Securities

6
Global Securities

12
Plan of Distribution

13
Where You Can Find More Information

15
Legal Matters

15
Experts

16

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Final Prospectus Supplement
Table of Contents
ABOUT THIS PROSPECTUS SUPPLEMENT
This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of
this offering. The second part, the accompanying prospectus, gives more general information, some of which
may not apply to this offering. You should read the entire prospectus supplement, as well as the accompanying
prospectus and the documents incorporated by reference that are described under "Where You Can Find More
Information" in the accompanying prospectus. Some of these documents, however, are filed on a combined basis
with our parent, Alliant Energy Corporation, and its direct subsidiary, Wisconsin Power and Light Company.
Information contained in these documents relating to these entities is filed by them on their own behalf and not
by us. The senior debentures are not obligations of, or guaranteed by, Alliant Energy Corporation or Wisconsin
Power and Light Company and you should not rely on that information when deciding whether to invest in our
senior debentures. In the event that the description of the offering varies between this prospectus supplement and
the accompanying prospectus, you should rely on the information contained in this prospectus supplement.
You should rely only on the information relating to Interstate Power and Light Company contained or
incorporated by reference in this prospectus supplement and the accompanying prospectus. We have not, and the
underwriters have not, authorized any other person to provide you with different information. If anyone provides
you with different or inconsistent information, you should not rely on it. We are not, and the underwriters are not,
making an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should
assume that the information appearing in this prospectus supplement, the accompanying prospectus and the
documents incorporated by reference is accurate only as of respective dates of those documents in which the
information is contained. Our business, financial condition, results of operations and prospects may have changed
since those dates.
Unless we otherwise indicate or unless the context requires otherwise, all references in this prospectus
supplement to "we," "our," "us" or similar references mean Interstate Power and Light Company.
Our principal executive offices are located at Alliant Energy Tower, 200 First Street, SE, Cedar Rapids, Iowa
52401, and our telephone number is (319) 786-4411.

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Final Prospectus Supplement
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FORWARD-LOOKING STATEMENTS
This prospectus supplement, the accompanying prospectus and the information we incorporate by reference into
this prospectus supplement and the accompanying prospectus contain forward-looking statements that are
intended to qualify for the safe harbors from liability established by the Private Securities Litigation Reform Act
of 1995. All statements other than statements of historical fact, including statements regarding anticipated
financial performance, business strategy and management's plans and objectives for future operations, are
forward-looking statements. These forward-looking statements can be identified as such because the statements
generally include words such as "expect," "intend," "believe," "anticipate," "estimate," "plan" or "objective" or
other similar expressions. These forward-looking statements are subject to risks and uncertainties that could
cause actual results to differ materially from those expressed in, or implied by, these statements. Additional
information concerning factors that could cause actual results to differ materially from those in the forward-
looking statements is contained from time to time in our U.S. Securities and Exchange Commission, or SEC,
filings, including, but not limited to, the risk factor disclosure beginning on page 20 of our Annual Report on
Form 10-K for the fiscal year ending December 31, 2008. Some, but not all, of the risks and uncertainties include
the following:

· federal and state regulatory or governmental actions, including the impact of energy-related and tax

legislation and regulatory agency orders;

· our ability to obtain adequate and timely rate relief to allow for, among other things, the recovery of
operating costs, deferred expenditures and capital expenditures, including any construction costs

incurred over the predetermined level included in the advanced rate making principles for our
Whispering Willow - East wind project, and the earning of reasonable rates of return;

· developments that adversely impact our ability to implement our strategic plans, including unanticipated

issues in connection with our construction of new generating facilities;

· our ability to reduce the impact of transmission rate increases for 2009;

· the state of the economy in our service territories and resulting implications on our sales and our ability

to collect unpaid bills, in particular as a result of the current recession;

· issues related to the availability of our generating facilities and the supply and delivery of fuel and

purchased electricity and price thereof, including the ability to recover and retain purchased power, fuel
and fuel-related costs through rates in a timely manner;

· the impact fuel and fuel-related prices and other economic conditions may have on our customers'

demand for utility services;

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Final Prospectus Supplement
· impacts that storms or natural disasters in our service territories may have on our operations, including
uncertainties associated with efforts to remediate the effects of the June 2008 Midwest flooding,
reimbursement of storm-related costs covered by insurance, anticipated amount of operating and

maintenance expenses associated with the flooding, levels of steam margins, rate relief for costs
associated with restoration, any asset impairment charges with respect to our steam distribution and
generating systems and impacts of the flooding on the economic conditions of the affected service
territories;

· issues associated with environmental remediation efforts and with environmental compliance generally,

including changing environmental laws and regulations and the ability to recover through rates all
environmental compliance costs;

· potential impacts of any future laws or regulations regarding global climate change or carbon emissions

reductions;

· the growth rate of ethanol and biodiesel production in our service territories;

· continued access to the capital markets under competitive terms and rates;

· weather effects on results of operations;

iii
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· financial impacts of hedging strategies, including the impact of weather hedges on our earnings;

· issues related to electric transmission, including operating in the Midwest Independent Transmission

System Operator, or MISO, energy and ancillary services markets, the impacts of potential future billing
adjustments from MISO and recovery of costs incurred;

· unplanned outages at our generating facilities and risks related to recovery of incremental costs through

rates;

· current or future litigation, regulatory investigations, proceedings or inquiries;

· Alliant Energy Corporation's ability to successfully defend against, and any liabilities arising out of, the

alleged violation of the Employee Retirement Income Security Act of 1974 by Alliant Energy
Corporation's Cash Balance Pension Plan;

· the direct or indirect effects resulting from terrorist incidents or responses to such incidents;

· employee workforce factors, including changes in key executives, collective bargaining agreements or

work stoppages;

· access to technological developments;

· any material post-closing adjustments related to any of our past asset divestitures;

· the impact of necessary accruals for the terms of our incentive compensation plans;

· the effect of accounting pronouncements issued periodically by standard-setting bodies;

· our ability to continue cost controls and operational efficiencies;

· increased retirement plan costs due to decreases in market value of plan assets;

· our ability to successfully complete ongoing tax audits and appeals with no material impact on our

earnings and cash flows; and

· inflation and interest rates.
We assume no obligation, and disclaim any duty, to update these forward-looking statements.

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PROSPECTUS SUPPLEMENT SUMMARY
This summary highlights information contained elsewhere in this prospectus supplement and the
accompanying prospectus. This summary may not contain all of the information that may be important to
you. You should read this entire prospectus supplement and the accompanying prospectus carefully before
making a decision to invest in our senior debentures.
Our Company
We are a public utility serving customers in Iowa and southern Minnesota. We are engaged principally in:

· the generation and distribution of electric energy in selective markets in Iowa and southern

Minnesota;

· the distribution and transportation of natural gas in selective markets in Iowa and southern

Minnesota; and

· the provision of steam services to certain customers in Cedar Rapids, Iowa and various other energy-

related products and services.
As of December 31, 2008, we served approximately 525,000 retail electric customers in approximately 750
communities and approximately 233,000 retail gas customers in approximately 240 communities.
All of our common stock is owned by Alliant Energy Corporation, a regulated investor-owned public utility
holding company with subsidiaries, including us, serving primarily electric and natural gas customers in the
Midwest.
We are subject to the jurisdiction of the Iowa Utilities Board, or IUB, and the Minnesota Public Utilities
Commission, or MPUC, with respect to various portions of our operations. We are also subject to the
jurisdiction of the Federal Energy Regulatory Commission, or FERC. Our parent corporation, Alliant Energy
Corporation, is a "holding company" and we are a "subsidiary company" within the Alliant Energy
Corporation "holding company system" as defined under the Public Utility Holding Company Act of 2005.
As a result, we are subject to some of the regulatory provisions of that Act.
The Offering
The following is a brief summary of some of the terms of this offering. For a more complete description of
the terms of the senior debentures, see "Description of the Senior Debentures" in this prospectus supplement
and "Description of Debt Securities" in the accompanying prospectus.

Issuer
Interstate Power and Light Company

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Senior debentures offered
$300 million aggregate principal amount of 6.25% senior
debentures due July 15, 2039.

Maturity
July 15, 2039.

Interest payment dates
January 15 and July 15 of each year, beginning on January 15,
2010.

Ranking
The senior debentures will be our unsecured senior obligations and
rank equally with our other unsecured senior indebtedness from
time to time outstanding. The senior debentures will also be
subordinated to any secured indebtedness to the extent of the assets
securing such indebtedness. We do not currently have any secured
indebtedness.

S-1
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Optional redemption
The senior debentures will be redeemable, at our option, in whole
or in part at any time and from time to time, at the redemption
prices described in "Description of Senior Debentures--Optional
Redemption."

Covenants
The indenture governing the senior debentures contains covenants
that, among other things, limit our ability to:

· create certain types of secured indebtedness without providing for the

senior debentures to be equally and ratably secured; and

· consolidate, merge or sell assets.
These covenants are subject to important exceptions and
qualifications, which are described under the heading "Description
of Debt Securities" in the accompanying prospectus.

No limitation on debt
The indenture governing the senior debentures does not limit the
amount of senior debentures that we may issue or provide holders
any protections should we be involved in a highly leveraged
transaction.

Ratings
Moody's Investors Service, Inc. has assigned the senior debentures a
rating of A3. Standard & Poor's Ratings Services has assigned the
senior debentures a rating of BBB+. Ratings are not a
recommendation to buy, sell or hold the senior debentures. We cannot
give any assurance that the ratings will be retained for any time period
or that they will not be revised or withdrawn by the ratings agencies.

Use of proceeds
We estimate that we will receive net proceeds from this offering of
approximately $295.2 million, after deducting the underwriting
discount and estimated offering expenses payable by us. We intend
to use the proceeds from this offering initially to repay short-term
debt, including that incurred to fund capital expenditures on an
interim basis, and invest in short-term assets and thereafter to
redeem $135.0 million of long-term debt and fund capital
expenditures, including new wind generation, environmental
projects and other utility capital projects, and for general working
capital purposes.

Denominations
The senior debentures will be issued in minimum denominations of
$1,000 and integral multiples of $1,000.
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Document Outline

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- #1">Final Prospectus Supplement