2. investing for our future.
We’re working with customers,
regulators, legislators and others
to invest in a brighter future.
3. investing for our future.
By investing in our infrastructure
and in the communities we serve,
we’re building a stronger company
for a better tomorrow.
Investing to Meet Customer Needs PAGE TWO
Investing in Environmental Stewardship PAGE FOUR
Investing in Infrastructure PAGE SIX
Letter to Shareholders PAGE NINE
Financial Highlights PAGE FOURTEEN
Investing in Returns for Shareholders PAGE FIFTEEN
Ameren Corporation and
Subsidiaries Officers and Directors PAGE SIXTEEN
Form 10-K
Investor Information INSIDE BACK COVER
Ameren 2007 PAGE ONE
4. investing to meet customer needs.
“We are committed to delivering
electricity and natural gas in a safe,
reliable and effi cient manner while
striving to improve our customer
service and satisfaction. It is essential
that we keep our focus to elevate
performance in all that we do.”
Scott A. Cisel
President and Chief Executive Officer
Ameren Illinois Utilities
Ameren 2007 PAGE TWO
5. investing for our future.
customer on computer, tree
trimming visible through window
The Ameren Illinois utilities, like all the Ameren
companies, put top priority on working safely
and elevating customer satisfaction as a
cornerstone of future success. The companies
are also positioning themselves as trusted
advisors in helping customers understand
energy usage and conservation. Since 2004,
the Illinois companies have spent more than
$1 billion on electric and natural gas infrastruc-
ture upgrades and new developments. They plan
to continue making meaningful investments in
Ameren 2007 PAGE THREE
their electric and natural gas delivery systems
in the coming years.
6. child on rope swing,
Sioux Plant visible in
background
In 2007 AmerenUE launched Power On, a
,
three-year, $1 billion commitment to improve
reliability, upgrade the company’s delivery
system and enhance the environmental
performance of its power plants. AmerenUE
also plans to spend at least $13 million annually
beginning in 2008, increasing to $56 million
annually by 2015, on energy efficiency
programs in Missouri. That level of investment
should place Missouri among the top 10 states
in the nation in per-capita spending on energy
Ameren 2007 PAGE FOUR
efficiency. Finally, AmerenUE committed to add
at least 100 megawatts of wind power to its
generation mix by 2010 and, in 2007, rolled
out Pure Power TM, a voluntary renewable energy
credit program for customers.
7. investing for our future.
investing in environmental stewardship.
“Ameren companies have always
been leaders in reducing power
plant emissions and testing emerging
environmental technologies even
before government regulations
required us to do so.”
Thomas R. Voss
President and Chief Executive Officer
AmerenUE
Ameren 2007 PAGE FIVE
8. investing in infrastructure.
“ In 2007, our fleet of non-rate-regulated
power plants contributed more than 40%
of Ameren’s earnings. Our strategy is to
continue optimizing the performance of
those plants—more than 6,000 megawatts
of generating capacity—while keeping
our commitment to be good stewards of
the environment.”
R. Alan Kelley
President and Chief Executive Officer
AmerenEnergy Resources
Ameren 2007 PAGE SIX
9. investing for our future.
To be Determined
Ameren’s non-rate-regulated power plants,
most of them in Illinois, will benefit from more
than $2 billion to be spent over the next
five years to add pollution control equipment
to meet federal requirements for significantly
reducing plant emissions, including mercury.
For example, at AmerenEnergy Generating
Company’s Coffeen Power Station (above),
a new scrubber will remove more than
95 percent of the plant’s sulfur dioxide
emissions by late 2009.
Ameren 2007 PAGE SEVEN
11. investing for our future.
“ Our company’s values and focus on
our core energy business has served
as a guide as we addressed the challenges
of the past year. Through it all, we have
remained committed to achieving strong
returns for you.”
Gary L. Rainwater
Chairman, Chief Executive Officer and President
Ameren Corporation
To My Fellow Shareholders,
2007 was a pivotal year for Ameren Corporation substantially covered by insurance. The recon-
in the sense that we put in place several struction of the plant will also serve as an engine
important building blocks for future success. for economic growth for Southeast Missouri.
In Illinois, we reached a comprehensive And for all our customers, in the wake
■ ■
settlement with key stakeholders that will help of the severe storms that hit our system in both
our customers’ transition to new electric rates states, we significantly increased investments
and bring stability to the power procurement to harden our electrical delivery system in order
process. This settlement provides significantly to provide industry-leading reliability and service.
greater levels of legislative, regulatory and legal Our belief is that by investing in infrastruc-
certainty, while enabling a viable, competitive ture, we can make material improvements in
power supply market to continue to develop service, which, in turn, will bring meaningful
in Illinois. improvement in customer satisfaction. As in
In Missouri, we settled all state and federal any business, serving customers well is critical
■
issues associated with the 2005 Taum Sauk to achieving solid returns for investors. I believe
plant reservoir breach and began rebuilding this improved customer service and satisfaction
valuable power facility. The project, scheduled will enable us to bring our rates of return more
Ameren 2007 PAGE NINE
for completion in the fall of 2009, is expected in line with returns normally allowed by utility
to cost approximately $450 million and to be regulatory commissions.
12. One example of this increased investment pace. Since our customers’ rates are typically
is Power On, AmerenUE’s three-year, $1 billion set based on historical cost levels through a
investment to improve the reliability of the nearly one-year regulatory review, by the time
company’s Missouri electric delivery system new rates are put in place, they are already
and reduce emissions at its coal-fired plants. inadequate to fully recover current costs and
Ameren’s Illinois utilities—AmerenCIPS, earn a fair return on investment. Of course, rate
AmerenCILCO and AmerenIP—also plan to increases are not popular among customers,
spend $1 billion on infrastructure improvements even when rates have been far below the
beween 2008 and 2010. industry norm for many years. Therefore, in order
These and future investments will contribute to allow our customers to more easily adjust to
to long-term earnings growth. In the near term, higher energy prices, and to allow shareholders
however, our rates are well below the levels to earn a fair profit, we must not wait decades
necessary to recover current costs and to earn for rate increases, but seek smaller and more
a fair return on investment. Returns in 2007 frequent increases. We must also seek auto-
and expected returns in 2008 in our regulated matic cost recovery mechanisms for large dollar
Missouri and Illinois businesses are well below
items, like fuel and environmental investments.
the levels allowed by both state utility commis-
Consequently, in late 2007, we filed with the
sions in our last rate cases.
Illinois Commerce Commission for an aggre-
A Need to Recover Rising Costs gate $247 million increase in delivery rates for
electricity and natural gas. We also requested
For decades, we have been industry leaders
cost recovery mechanisms for bad debts, electric
in keeping our rates low through disciplined
infrastructure investments and gas decoupling.
cost control and efficient operations. Even
In Missouri, we plan to file for an electric rate
after recent rate increases, AmerenUE’s electric
increase in the second quarter of 2008. We will
rates are still about 40 percent below the
national average, and rates for our Illinois also request that a fuel cost recovery mechanism,
utilities approximate the national average. and potentially an environmental cost recovery
However, today, costs of every element mechanism, be implemented to recover our costs
of our business are rising at an unprecedented in a more timely manner.
Since it went online in 1984, AmerenUE’s Callaway Nuclear Plant has achieved
the fourth highest generation record among the 104 nuclear power units operating
in the U.S., having now generated more than 200 million megawatthours.
Ameren 2007 PAGE TEN
Callaway’s lifetime generation through 2006 ranks it 20th in the world out of 445
nuclear units operating in 30 countries. Though no decision has been made to
add a second unit at the site, in 2007 AmerenUE took steps to preserve that option.
13. investing for our future.
The bottom line is that we are now in a rising Power On sets aside $500 million for environ-
cost environment following many years of mental improvements, including a scrubber we
declining costs for our customers. As a result, are installing at AmerenUE’s Sioux Plant.
it is now more important than ever to obtain We are also installing scrubbers on the
constructive outcomes for our rate cases in non-rate-regulated generation side of our
Illinois and Missouri. We must recover our business at the Duck Creek Plant and Coffeen
costs and realize appropriate returns on our Power Station. These technologies will remove
investments in order to continue investing at least 95 percent of the plants’ sulfur dioxide
in our energy infrastructure on a timely basis emissions.
to provide our customers with the safe, Our environmental plans are discussed in
reliable service they expect. more detail in our first comprehensive environ-
mental report, “Stewardship: Balancing the
Needs of Our Environment, Our Customers
We will protect our customers’ and and Our Economy.” This publication—which
you can view at www.ameren.com/EnvReport
your interests in arguing our case
—also states that Ameren would firmly support
for a balanced, reasoned approach a mandated reduction in carbon dioxide ( CO2 )
to reductions of greenhouse gases. emissions as long as that requirement effectively
balances the benefits to the environment against
cost to consumers and the risk of economic
Planning for a Cleaner Environment disruption to the economy in the Midwest and
Programs, like Power On, demonstrate that throughout the nation.
we are responding to our customers’ need After extensive analysis, we have concluded
for improved reliability—burying lines where that any federal climate legislation must include
appropriate, increasing our pole and line reductions for all greenhouse gas sources, set
maintenance programs, stepping up our tree- compliance timelines consistent with development
trimming and removals and more. and deployment of advanced technologies, be
However, we also know that our customers global in approach and recognize the significant
are concerned about the environment. economic impact reducing CO2 will have on our
With support from the Missouri Department of Natural Resources, the Department
of Conservation, AmerenUE and its contractors, and others, the state of Missouri
Ameren 2007 PAGE ELEVEN
reopened Johnson’s Shut-Ins State Park for swimming in 2007. The popular
tourist site was severely damaged by the 2005 breach of AmerenUE’s Taum Sauk
pumped-storage plant’s upper reservoir. The company has now settled all issues
with the state of Missouri, and work is under way to bring this critical plant back
in service by late 2009.
14. region’s consumers and businesses. Our current details how the company expects to supply
analysis shows that under some policy scenarios safe, reliable electricity in coming years, while
being considered, because of the dependence protecting the environment.
on coal-fired generation in the Midwest, house-
hold costs could rise significantly and rates for
We will study a wide range
electricity could double by 2030.
We will protect our customers’ and your
of technologies to meet our
interests in arguing our case for a balanced,
customers’ energy needs in the
reasoned approach to reductions of greenhouse
future, including advanced coal
gases, and we look forward to continuing our
active engagement in discussions about this
technologies and nuclear power.
important issue at both federal and state levels.
I encourage you to also get involved in this
important debate. In summary, the plan recommends aggres-
sively pursuing energy efficiency programs,
Future Generation to Meet
Our Customer Needs expanding the role of renewable energy,
Related to the topic of the environmental increasing operational efficiency at existing
report is the question of Ameren’s next plants, and evaluating a range of options for
addition of baseload generation—the “work- new baseload generating facilities.
horse” plants that operate virtually year- We will study a wide range of technologies
round, 24 hours a day, so that Ameren’s to meet our customers’ energy needs in the
customers have the power they need, future, including advanced coal technologies
when they need it. and nuclear power. As a result of the long
In February 2008, AmerenUE filed an time required to design, license and build a
integrated resource plan with the Missouri baseload power plant, this year we expect
Public Service Commission. It was developed to file a construction and operating license
with significant stakeholder input from a application with the Nuclear Regulatory Commis-
broad spectrum of organizations. This plan sion for a new nuclear unit at our Callaway site.
Ameren employees are active in their communities. AmerenUE Vice President,
Public Relations Karen Foss (above left) helps Boy Scouts place energy
Ameren 2007 PAGE TWELVE
efficient, long-lasting compact fluorescent light bulbs in boxes of food headed
to needy senior citizens. Employees volunteer for countless community
projects across the company’s 64,000-square-mile service territory, from planting
trees (above right) to participating in food and blood drives.
15. investing for our future.
While this does not mean we have made a final as well as through improving the returns in
decision to add a second unit at Callaway, it these businesses as a result of more frequent,
preserves that option for us. but smaller rate increases. We also expect to
continue to improve the operation of our non-
Optimizing Our Power Generation
rate-regulated generating plants and position
Business
them for earnings growth should power markets
In our non-rate-regulated generation operations,
improve in the years ahead.
we continued, in 2007, to invest in our plants
When we put all that together, we see
to improve their productivity, as well as to
average earnings growth on the order of
effectively market the power they produce.
4% to 6% per year through 2010, achieving
Looking ahead, we will continue to focus
earnings of approximately $3.70 per share
on optimizing this business by increasing plant
by 2010. By 2011, we believe we will be able
availability and plant output. By 2010, we expect
to achieve $4 per share with continued earnings
our non-rate-regulated plant output to increase
growth thereafter. We are committed to realizing
approximately 10 percent over 2007 levels, to
this goal. We are committed to providing the
nearly 33 million megawatthours.
strong sustainable dividend we have for the
And while we currently believe that rising
past century. And we are committed to laying
costs, including fuel, depreciation and financing
a solid foundation for future dividend growth.
costs, will largely offset these productivity gains
I thank you for your continued support,
in the near-term, we believe our plants will be
and I hope you can attend this year’s Annual
well-positioned for earnings growth in the future
Shareholders Meeting on April 22 at The
should energy and capacity prices improve.
St. Louis Art Museum.
A Bright Future
I believe that in 2007 we laid a solid foundation
for future success. Looking ahead, we expect
to achieve significant earnings growth in our
business. That growth is expected to come Gary L. Rainwater
Chairman, Chief Executive Officer and President
primarily from our regulated businesses through
Ameren Corporation
the higher levels of investment I have outlined,
From left, Dick Fleming, chief executive officer of the St. Louis Regional
Ameren 2007 PAGE THIRTEEN
Chamber and Growth Association; the Honorable Francis Slay, mayor of the
City of St. Louis; Tom Voss, AmerenUE president and chief executive officer;
Richard Mark, AmerenUE senior vice president, Missouri Energy Delivery; and
Charlie Dooley, St. Louis County Executive, kick off Power On—AmerenUE’s
$1 billion commitment to improving distribution system reliability and enhancing
the environmental performance of its power plants.
16. Financial Highlights
Ameren Consolidated Year Ended December 31,
(In millions, except per share amounts and as noted) 2007 2006 2005
RESULTS OF OPERATIONS
Operating revenues $7,546 $6,880 $6,780
Operating expenses $6,204 $5,707 $5,496
Operating income $1,342 $1,173 $1,284
Income before cumulative effect of change in accounting principle $618 $547 $628
Cumulative effect of change in accounting principle,
net of income tax benefit $– $– $(22)
Net income $618 $547 $606
COMMON STOCK DATA
Earnings per basic and diluted share (a) $2.98 $2.66 $3.13
Dividends per common share $2.54 $2.54 $2.54
Dividend yield (year-end) 4.7% 4.7% 5.0%
Market price per common share (year-end closing) $54.21 $53.73 $51.24
Shares outstanding (weighted average) 207.4 205.6 200.8
Total market value of common shares (year-end) $11,294 $11,099 $10,489
Book value per common share $32.41 $31.87 $31.09
BALANCE SHEET DATA
Property and plant, net $15,069 $14,286 $13,581
Total assets $20,728 $19,635 $18,171
Long-term debt obligations, excluding current maturities $5,691 $5,285 $5,354
Capitalization ratios
Common equity 48.2% 50.6% 52.5%
Preferred stock, not subject to mandatory redemption 1.4% 1.5% 1.6%
Debt and preferred stock subject to mandatory redemption, net of cash 50.4% 47.9% 45.9%
OPERATING DATA
Total electric sales (KwH) 107,486 101,015 96,059
Native gas sales (thousands of MMBtus) 107,871 108,682 114,182
Total generation output (KwH) 81,367 81,485 77,941
Electric customers 2.4 2.4 2.4
Gas customers 1.0 1.0 1.0
Ameren 2007 PAGE FOURTEEN
(a) 2005 excludes charges for the cumulative effect of a change in accounting
principle of $22 million (11 cents per share), net of income tax benefit.
17. investing for our future.
investing in returns for shareholders.
“ We are investing our resources
wisely for the benefit of all of our
stakeholders. We will remain focused
on achieving solid returns on our
investments and producing long-term
earnings growth, as well as continuing
to provide a strong, sustainable dividend.”
Warner L. Baxter
Executive Vice President and Chief Financial Officer
Ameren Corporation
TOTAL CAPITAL
GENERATION INVESTMENTS
OUTPUT
$1,381
AMEREN’S 2007
SEGMENT EARNINGS
81,485
81,367
(In millions)
81 4
77 941
$1, 284
,
$1 2
$935
$47
Illinois Regulated
Non-Rate-Regulated
(KwH in millions)
$281
Generation
(In millions)
$281
Missouri Regulated
Ameren 2007 PAGE FIFTEEN
$9
Other
05 06 07 05 06 07
18. Ameren Corporation and Subsidiaries Officers and Directors
Richard J. Mark*
EXECUTIVE Thomas R. Voss Donna K. Martin
Senior Vice President,
Executive Vice President Senior Vice President
LEADERSHIP TEAM
AmerenUE
and Chief Operating Officer, and Chief Human
Gary L. Rainwater
AmerenUE President and Resources Officer Michael L. Moehn*
Chairman, President
Chief Executive Officer Vice President,
Steven R. Sullivan
and Chief Executive Officer
Corporate Planning,
Senior Vice President,
Scott A. Cisel *
Warner L. Baxter Ameren Services
General Counsel and Secretary
President and Chief
Executive Vice President
Executive Officer, Charles D. Naslund*
Daniel F. Cole*
and Chief Financial Officer,
AmerenCILCO, AmerenCIPS Senior Vice President
Senior Vice President,
Ameren Services President
and AmerenIP and Chief Nuclear Officer,
Administration and Technical
and Chief Executive Officer
AmerenUE
Services, Ameren Services
R. Alan Kelley *
Andrew M. Serri *
Martin J. Lyons
President and Chief
President,
Senior Vice President
Executive Officer,
AmerenEnergy Marketing
and Chief Accounting Officer
AmerenEnergy Resources
Scott A. Glaeser * William J. Prebil *
Michael G. Mueller *
OTHER OFFICERS
Vice President, Gas Supply Vice President,
President, AmerenEnergy
Lynn M. Barnes*
and System Control, Regional Operations,
Fuels and Services
Vice President Business Planning
AmerenEnergy Fuels AmerenCILCO,
Robert K. Neff *
and Controller, AmerenUE
and Services AmerenCIPS, AmerenIP
Vice President, Coal Supply
Jerre E. Birdsong
Adam C. Heflin* David J. Schepers*
and Transportation,
Vice President and Treasurer
Vice President, AmerenEnergy Fuels and Services Vice President, Energy
Mark C. Birk* Nuclear Operations, AmerenUE Delivery Technical Services,
Craig D. Nelson*
Vice President,
Vice President, Regulatory Affairs Ameren Services
Timothy E. Herrmann*
Power Operations, AmerenUE
Shawn E. Schukar *
Vice President, Engineering, and Financial Services, Ameren-
Maureen A. Borkowski * Callaway Nuclear Plant, Vice President, Strategic
CILCO, AmerenCIPS, AmerenIP
Vice President, Transmission, AmerenUE Initiatives, Ameren Services
Stan E. Ogden*
Ameren Services
Christopher A. Iselin* Vice President, Customer Service Jerry L. Simpson*
S. Mark Brawley * Vice President, Human and Public Relations, AmerenCILCO, Vice President, Business
Vice President, Internal Audit, Resources, Business Services, Services, AmerenEnergy
AmerenCIPS, AmerenIP
Ameren Services Ameren Services Resources
Ronald D. Pate*
Charles A. Bremer * Stephen M. Kidwell * James A. Sobule*
Vice President, Regional
Vice President, Information Vice President, Vice President and
Operations, AmerenCILCO,
Technology and Ameren Regulatory Affairs, AmerenUE Deputy General Counsel,
AmerenCIPS, AmerenIP
Services Center, Ameren Services Ameren Services
Mark C. Lindgren* Gregory L. Nelson*
Richard C. Cissell* Vice President, Corporate Bruce A. Steinke
Vice President and Tax Counsel,
Vice President, Operations, Human Resources, Vice President and Controller
Ameren Services
AmerenEnergy Generating Ameren Services Dennis W. Weisenborn*
Joseph M. Power *
Ronald K. Evans* Michael L. Menne* Vice President,
Vice President, Federal
Vice President and Vice President, Supply Services, Ameren
Legislative and Regulatory
Deputy General Counsel, Environmental Safety and Health, Services
Affairs, Ameren Services
Ameren Services Ameren Services Ronald C. Zdellar *
Robert L. Powers*
Donald M. Mosier * Vice President, Energy
Vice President, Generation
Karen C. Foss*
Vice President, Delivery Distribution Services,
Technical Services,
Vice President, Public Relations,
AmerenEnergy Marketing AmerenUE
AmerenEnergy Resources
AmerenUE
Jack D. Woodard 5, 6
Dr. Gayle P. W. Jackson 5, 6 Charles W. Mueller 1, 5, 6
BOARD OF DIRECTORS
Retired Executive Vice President
President, Energy Global, Inc. Retired Chairman and
Stephen F. Brauer 2, 5
and Chief Nuclear Officer, Southern
Chief Executive Officer,
James C. Johnson 4, 5
Chairman and Chief
Nuclear Operating Company, Inc.
Ameren Corporation
Vice President and
Executive Officer, Hunter
Douglas R. Oberhelman 1, 2, 5
Assistant General Counsel,
Engineering Company
Group President, Caterpillar Inc.
Commercial Airplanes,
2, 6
Susan S. Elliott 1 Member of Executive Committee
The Boeing Company Gary L. Rainwater 1
Chairman and 2 Member of Audit and Risk Committee
Chairman, President
Richard A. Liddy 1, 2, 3
Co-Chief Executive Officer, 3 Member of the Human Resources
and Chief Executive Officer,
Retired Chairman,
Systems Service Committee
Ameren Corporation
GenAmerica Financial
Enterprises, Inc. 4 Member of the Nominating and
Ameren 2007 PAGE SIXTEEN
Corporation Harvey Saligman 1, 3, 4 Corporate Governance Committee
Walter J. Galvin
Partner, Cynwyd Investments 5 Member of the Public Policy Committee
Gordon R. Lohman 1, 3, 4, 7
Senior Executive Vice
Patrick T. Stokes 3, 5
Retired Chairman and
President and Chief 6 Member of the Nuclear Oversight
Committee
Chief Executive Officer, Chairman, Anheuser-Busch
Financial Officer, Emerson
AMSTED Industries Inc. Companies, Inc.
Electric Co. 7 Lead Director
* Officer of an Ameren Corporation subsidiary only
19. UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 10-K
(X) Annual report pursuant to Section 13 or 15(d)
of the Securities Exchange Act of 1934
for the fiscal year ended December 31, 2007
OR
() Transition report pursuant to Section 13 or 15(d)
of the Securities Exchange Act of 1934
for the transition period from to .
Exact name of registrant as specified in its charter;
Commission State of Incorporation; IRS Employer
File Number Address and Telephone Number Identification No.
1-14756 Ameren Corporation 43-1723446
(Missouri Corporation)
1901 Chouteau Avenue
St. Louis, Missouri 63103
(314) 621-3222
1-2967 Union Electric Company 43-0559760
(Missouri Corporation)
1901 Chouteau Avenue
St. Louis, Missouri 63103
(314) 621-3222
1-3672 Central Illinois Public Service Company 37-0211380
(Illinois Corporation)
607 East Adams Street
Springfield, Illinois 62739
(888) 789-2477
333-56594 Ameren Energy Generating Company 37-1395586
(Illinois Corporation)
1901 Chouteau Avenue
St. Louis, Missouri 63103
(314) 621-3222
2-95569 CILCORP Inc. 37-1169387
(Illinois Corporation)
300 Liberty Street
Peoria, Illinois 61602
(309) 677-5271
1-2732 Central Illinois Light Company 37-0211050
(Illinois Corporation)
300 Liberty Street
Peoria, Illinois 61602
(309) 677-5271
1-3004 Illinois Power Company 37-0344645
(Illinois Corporation)
370 South Main Street
Decatur, Illinois 62523
(217) 424-6600
20. Securities Registered Pursuant to Section 12(b) of the Securities Exchange Act of 1934:
Each of the following classes or series of securities is registered pursuant to Section 12(b) of the Securities Exchange Act
of 1934 and is listed on the New York Stock Exchange:
Registrant Title of each class
Ameren Corporation Common Stock, $0.01 par value per share and Preferred
Share Purchase Rights
Securities Registered Pursuant to Section 12(g) of the Securities Exchange Act of 1934:
Registrant Title of each class
Union Electric Company Preferred Stock, cumulative, no par value,
Stated value $100 per share –
$4.56 Series $4.50 Series
$4.00 Series $3.50 Series
Central Illinois Public Service Company Preferred Stock, cumulative, $100 par value per share –
6.625% Series 4.90% Series
5.16% Series 4.25% Series
4.92% Series 4.00% Series
Depository Shares, each representing one-fourth of a
share of 6.625% Preferred Stock, cumulative,
$100 par value per share
Central Illinois Light Company Preferred Stock, cumulative, $100 par value per share –
4.50% Series
Ameren Energy Generating Company, CILCORP Inc., and Illinois Power Company do not have securities registered under
either Section 12(b) or 12(g) of the Securities Exchange Act of 1934.
Indicate by check mark if each registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act of
1933.
Ameren Corporation Yes (X) No ()
Union Electric Company Yes (X) No ()
Central Illinois Public Service Company Yes () No (X)
Ameren Energy Generating Company Yes () No (X)
CILCORP Inc. Yes () No (X)
Central Illinois Light Company Yes () No (X)
Illinois Power Company Yes () No (X)
Indicate by check mark if each registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the
Securities Exchange Act of 1934.
Ameren Corporation Yes () No (X)
Union Electric Company Yes () No (X)
Central Illinois Public Service Company Yes () No (X)
Ameren Energy Generating Company Yes (X) No ()
CILCORP Inc. Yes (X) No ()
Central Illinois Light Company Yes () No (X)
Illinois Power Company Yes (X) No ()
Indicate by check mark whether the registrants: (1) have filed all reports required to be filed by Section 13 or 15(d) of the
Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to
file such reports), and (2) have been subject to such filing requirements for the past 90 days. Yes (X) No ( )
21. Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein,
and will not be contained, to the best of each registrant’s knowledge, in definitive proxy or information statements incorporated
by reference in Part III of this Form 10-K or any amendment to this Form 10-K.
Ameren Corporation (X)
Union Electric Company (X)
Central Illinois Public Service Company (X)
Ameren Energy Generating Company (X)
CILCORP Inc. (X)
Central Illinois Light Company (X)
Illinois Power Company (X)
Indicate by check mark whether each registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or a
smaller reporting company. See definitions of “accelerated filer”, “large accelerated filer” and “smaller reporting company” in
Rule 12b-2 of the Securities Exchange Act of 1934.
Large Smaller
Accelerated Accelerated Non-Accelerated Reporting
Filer Filer Filer Company
Ameren Corporation (X) () () ()
Union Electric Company () () (X) ()
Central Illinois Public Service Company () () (X) ()
Ameren Energy Generating Company () () (X) ()
CILCORP Inc. () () (X) ()
Central Illinois Light Company () () (X) ()
Illinois Power Company () () (X) ()
Indicate by check mark whether each registrant is a shell company (as defined in Rule 12b-2 of the Securities Exchange
Act of 1934).
Ameren Corporation Yes ( ) No (X)
Union Electric Company Yes ( ) No (X)
Central Illinois Public Service Company Yes ( ) No (X)
Ameren Energy Generating Company Yes ( ) No (X)
CILCORP Inc. Yes ( ) No (X)
Central Illinois Light Company Yes ( ) No (X)
Illinois Power Company Yes ( ) No (X)
As of June 29, 2007, Ameren Corporation had 207,510,090 shares of its $0.01 par value common stock outstanding. The
aggregate market value of these shares of common stock (based upon the closing price of these shares on the New York Stock
Exchange on that date) held by nonaffiliates was $10,170,069,511. The shares of common stock of the other registrants were
held by affiliates as of June 29, 2007.
The number of shares outstanding of each registrant’s classes of common stock as of January 31, 2008, was as follows:
Ameren Corporation Common stock, $0.01 par value per share: 208,728,929
Union Electric Company Common stock, $5 par value per share, held by Ameren
Corporation (parent company of the registrant):
102,123,834
Central Illinois Public Service Company Common stock, no par value, held by Ameren Corporation
(parent company of the registrant): 25,452,373
Ameren Energy Generating Company Common stock, no par value, held by Ameren Energy
Development Company (parent company of the registrant
and indirect subsidiary of Ameren Corporation): 2,000
CILCORP Inc, Common stock, no par value, held by Ameren Corporation
(parent company of the registrant): 1,000
Central Illinois Light Company Common stock, no par value, held by CILCORP Inc. (parent
company of the registrant and subsidiary of Ameren
Corporation): 13,563,871
Illinois Power Company Common stock, no par value, held by Ameren Corporation
(parent company of the registrant): 23,000,000
22. DOCUMENTS INCORPORATED BY REFERENCE
Portions of the definitive proxy statement of Ameren Corporation and portions of the definitive information statements of
Union Electric Company, Central Illinois Public Service Company, and Central Illinois Light Company for the 2008 annual
meetings of shareholders are incorporated by reference into Part III of this Form 10-K.
OMISSION OF CERTAIN INFORMATION
Ameren Energy Generating Company and CILCORP Inc. meet the conditions set forth in General Instruction I(1)(a) and
(b) of Form 10-K and are therefore filing this form with the reduced disclosure format allowed under that General Instruction.
This combined Form 10-K is separately filed by Ameren Corporation, Union Electric Company, Central Illinois Public Service
Company, Ameren Energy Generating Company, CILCORP Inc., Central Illinois Light Company, and Illinois Power Company. Each
registrant hereto is filing on its own behalf all of the information contained in this annual report that relates to such registrant.
Each registrant hereto is not filing any information that does not relate to such registrant, and therefore makes no representation
as to any such information.
25. GLOSSARY OF TERMS AND ABBREVIATIONS
We use the words “our,” “we” or “us” with respect to certain information that relates to all Ameren Companies, as defined
below. When appropriate, subsidiaries of Ameren are named specifically as we discuss their various business activities.
AERG – AmerenEnergy Resources Generating Company, a estimating electricity demand by residential and commercial
CILCO subsidiary that operates a non-rate-regulated electric customers for summer cooling.
generation business in Illinois. CT – Combustion turbine electric generation equipment used
AFS – Ameren Energy Fuels and Services Company, a primarily for peaking capacity.
CUB – Citizens Utility Board.
Resources Company subsidiary that procures fuel and
Development Company – Ameren Energy Development
natural gas and manages the related risks for the Ameren
Company was an Ameren Energy Resources Company
Companies.
subsidiary and parent of Genco, Marketing Company, AFS,
Ameren – Ameren Corporation and its subsidiaries on a
and Medina Valley. It was eliminated in an internal
consolidated basis. In references to financing activities,
reorganization in February 2008.
acquisition activities, or liquidity arrangements, Ameren is
DOE – Department of Energy, a U.S. government agency.
defined as Ameren Corporation, the parent.
DRPlus – Ameren Corporation’s dividend reinvestment and
Ameren Companies – The individual registrants within the
direct stock purchase plan.
Ameren consolidated group.
Dth (dekatherm) – one million BTUs of natural gas.
Ameren Illinois Utilities – CIPS, IP and the rate-regulated
Dynegy – Dynegy Inc.
electric and gas utility operations of CILCO.
EEI – Electric Energy, Inc., an 80%-owned Ameren
Ameren Services – Ameren Services Company, an Ameren
Corporation subsidiary (40% owned by UE and 40% owned
Corporation subsidiary that provides support services to
by Development Company) that operates non-rate-regulated
Ameren and its subsidiaries.
electric generation facilities and FERC-regulated transmission
AMIL – The balancing authority area operated by Ameren,
facilities in Illinois. In February 2008, UE’s 40% ownership
which includes the load of the Ameren Illinois Utilities and
interest and Development Company’s 40% ownership
the generating assets of AERG and Genco.
interest were transferred to Resources Company. The
AMMO – The balancing authority area operated by Ameren,
remaining 20% is owned by Kentucky Utilities Company.
which includes the load and generating assets of UE.
EITF – Emerging Issues Task Force, an organization designed
AMT – Alternative minimum tax.
to assist the FASB in improving financial reporting through
APB – Accounting Principles Board.
the identification, discussion and resolution of financial
ARB – Accounting Research Bulletin.
issues in keeping with existing authoritative literature.
ARO – Asset retirement obligations.
ELPC – Environmental Law and Policy Center.
Baseload – The minimum amount of electric power
EPA – Environmental Protection Agency, a U.S. government
delivered or required over a given period of time at a steady
agency.
rate.
Equivalent availability factor – A measure that indicates the
Btu – British thermal unit, a standard unit for measuring the
percentage of time an electric power generating unit was
quantity of heat energy required to raise the temperature of
available for service during a period.
one pound of water by one degree Fahrenheit.
ERISA – Employee Retirement Income Security Act of 1974,
Capacity factor – A percentage measure that indicates how
as amended.
much of an electric power generating unit’s capacity was Exchange Act – Securities Exchange Act of 1934, as
used during a specific period. amended.
CILCO – Central Illinois Light Company, a CILCORP FASB – Financial Accounting Standards Board, a rulemaking
subsidiary that operates a rate-regulated electric organization that establishes financial accounting and
transmission and distribution business, a non-rate-regulated reporting standards in the United States.
electric generation business through AERG, and a rate- FERC – The Federal Energy Regulatory Commission, a
regulated natural gas transmission and distribution business, U.S. government agency.
all in Illinois, as AmerenCILCO. CILCO owns all of the FIN – FASB Interpretation. An explanation intended to
common stock of AERG. clarify accounting pronouncements previously issued by the
CILCORP – CILCORP Inc., an Ameren Corporation subsidiary FASB.
that operates as a holding company for CILCO and various Fitch – Fitch Ratings, a credit rating agency.
non-rate-regulated subsidiaries. FSP – FASB Staff Position. A publication that provides
CIPS – Central Illinois Public Service Company, an Ameren application guidance on FASB literature.
Corporation subsidiary that operates a rate-regulated electric FTRs – Financial transmission rights, financial instruments
and natural gas transmission and distribution business in that entitle the holder to pay or receive compensation for
Illinois as AmerenCIPS. certain congestion-related transmission charges between two
CIPSCO – CIPSCO Inc., the former parent of CIPS. designated points.
CO2 – Carbon dioxide. Fuelco – Fuelco LLC, a limited-liability company that
Cooling degree-days – The summation of positive provides nuclear fuel management and services to its
differences between the mean daily temperature and a members. The members are UE, Texas Generation Company
65-degree Fahrenheit base. This statistic is useful for LP, and Pacific Energy Fuels Company.
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26. JDA – The joint dispatch agreement among UE, CIPS, and
GAAP – Generally accepted accounting principles in the
Genco under which UE and Genco jointly dispatched electric
United States.
generation prior to its termination on December 31, 2006.
Genco – Ameren Energy Generating Company, a Resources
Kilowatthour – A measure of electricity consumption
Company subsidiary that operates a non-rate-regulated
equivalent to the use of 1,000 watts of power over a period
electric generation business in Illinois and Missouri.
of one hour.
Gigawatthour – One thousand megawatthours.
Marketing Company – Ameren Energy Marketing Company,
Heating degree-days – The summation of negative
a Resources Company subsidiary that markets power for
differences between the mean daily temperature and a 65-
Genco, AERG and EEI.
degree Fahrenheit base. This statistic is useful as an
Medina Valley – Ameren Energy Medina Valley Cogen LLC,
indicator of demand for electricity and natural gas for winter
a Resources Company subsidiary, which owns a 40-
space heating for residential and commercial customers.
megawatt gas-fired electric generation plant.
IBEW – International Brotherhood of Electrical Workers, a
Megawatthour – One thousand kilowatthours.
labor union.
MGP – Manufactured gas plant.
ICC – Illinois Commerce Commission, a state agency that
MISO – Midwest Independent Transmission System
regulates the Illinois utility businesses and operations of
Operator, Inc.
CIPS, CILCO and IP.
MISO Day Two Energy Market – A market that began
Illinois Customer Choice Law – Illinois Electric Service
operating on April 1, 2005. It uses market-based pricing,
Customer Choice and Rate Relief Law of 1997, which
which incorporates transmission congestion and line losses,
provided for electric utility restructuring and introduced
to compensate market participants for power.
competition into the retail supply of electric energy in
Missouri Environmental Authority – Environmental
Illinois.
Improvement and Energy Resources Authority of the state of
Illinois electric settlement agreement – A comprehensive
Missouri, a governmental body authorized to finance
settlement of issues in Illinois arising out of the end of ten
environmental projects by issuing tax-exempt bonds and
years of frozen electric rates, effective January 2, 2007. The
notes.
Illinois electric settlement agreement, which became effective
Missouri Regulated – A financial reporting segment
on August 28, 2007, was designed to avoid new rate
consisting of all the operations of UE’s business, except for
rollback and freeze legislation and legislation that would
non-rate-regulated activities.
impose a tax on electric generation in Illinois. The settlement
Money pool – Borrowing agreements among Ameren and its
addresses the issue of future power procurement, and it
subsidiaries to coordinate and provide for certain short-term
includes a comprehensive rate relief and customer
cash and working capital requirements. Separate money
assistance program.
pools maintained for rate-regulated and non-rate-regulated
Illinois EPA – Illinois Environmental Protection Agency, a
businesses are referred to as the utility money pool and the
state government agency.
non-state-regulated subsidiary money pool, respectively.
Illinois Regulated – A financial reporting segment consisting
Moody’s – Moody’s Investors Service Inc., a credit rating
of the regulated electric and gas transmission and
agency.
distribution businesses of CIPS, CILCO and IP. MoPSC – Missouri Public Service Commission, a state
IP – Illinois Power Company, an Ameren Corporation
agency that regulates the Missouri utility business and
subsidiary. IP operates a rate-regulated electric and natural
operations of UE.
gas transmission and distribution business in Illinois as NCF&O – National Congress of Firemen and Oilers, a labor
AmerenIP. union.
IP LLC – Illinois Power Securitization Limited Liability NERC – North American Electric Reliability Corporation.
Company, which is a special-purpose Delaware limited- Non-rate-regulated Generation – A financial reporting
liability company. segment consisting of the operations or activities of Genco,
IP SPT – Illinois Power Special Purpose Trust, which was CILCORP holding company, AERG, EEI, and Marketing
created as a subsidiary of IP LLC to issue TFNs as allowed Company.
under the Illinois Customer Choice Law. Pursuant to FIN 46R, NOx – Nitrogen oxide.
IP SPT is a variable-interest entity, as the equity investment Noranda – Noranda Aluminum, Inc.
is not sufficient to permit IP SPT to finance its activities NRC – Nuclear Regulatory Commission, a U.S. government
without additional subordinated debt. agency.
IPA – Illinois Power Agency, a state government agency that NYMEX – New York Mercantile Exchange.
has broad authority to assist in the procurement of electric NYSE – New York Stock Exchange, Inc.
power for residential and nonresidential customers beginning OATT – Open Access Transmission Tariff.
in June 2009. OCI – Other comprehensive income (loss) as defined by
ISRS – Infrastructure system replacement surcharge. A GAAP.
cost recovery mechanism in Missouri that allows UE to Off-system revenues – Revenues from nonnative load sales.
recover gas infrastructure replacement costs from utility OTC – Over-the-counter.
customers without a traditional rate case. PGA – Purchased Gas Adjustment tariffs, which allow the
IUOE – International Union of Operating Engineers, a labor passing through of the actual cost of natural gas to utility
union. customers.
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