UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 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, 1999
OR
( ) Transition report pursuant to Section 13 or 15(d)
of the Securities Exchange Act of 1934
For the transition period from to .
------- --------

COMMISSION FILE NUMBER 1-14756

AMEREN CORPORATION
(Exact name of registrant as specified in its charter)

Missouri 43-1723446
(State or other jurisdiction (I.R.S. Employer Identification
of incorporation or organization) No.)

1901 Chouteau Avenue, St. Louis, Missouri 63103
(Address of principal executive offices and Zip Code)
Registrant's telephone number, including area code: (314) 621-3222

SECURITIES REGISTERED PURSUANT TO SECTION 12(b) OF THE ACT:

Title of each class Name of each exchange on which registered
- ----------------------------- -----------------------------------------
Common Stock, $ .01 par value New York Stock Exchange

SECURITIES REGISTERED PURSUANT TO SECTION 12(g) OF THE ACT: NONE.

Indicate by check mark whether the registrant (1) has 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) has been subject to such
filing requirements for the past 90 days. Yes [X]. No [ ].

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 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. [ ].

Aggregate market value of voting stock held by non-affiliates as of
March 6, 2000, based on closing prices most recently available as reported in
The Wall Street Journal: $3,867,760,835.

Shares of Common Stock, $ .01 par value, outstanding as of March 6,
2000: 137,215,462 shares.

DOCUMENTS INCORPORATED BY REFERENCES.

Portions of the registrant's 1999 Annual Report to Stockholders (the
"1999 Annual Report") are incorporated by reference into Parts I, II and IV.

Portions of the registrant's definitive proxy statement for the 2000
annual meeting are incorporated by reference into Part III.

TABLE OF CONTENTS

PART I PAGE
----

Item 1 - Business
General............................................................................... 1
Capital Program and Financing......................................................... 2
Rates................................................................................. 3
Fuel Supply........................................................................... 3
Regulation............................................................................ 4
Industry Issues....................................................................... 6
Operating Statistics(1)............................................................... 6

Item 2 - Properties.................................................................................. 6
Item 3 - Legal Proceedings........................................................................... 8
Item 4 - Submission of Matters to a Vote of Security Holders(2)

Executive Officers of the Company (Item 401(b) of Regulation S-K)......................................... 9

PART II

Item 5 - Market for Registrant's Common Equity and Related
Stockholder Matters(1)................................................................ 10
Item 6 - Selected Financial Data(1).................................................................. 11
Item 7 - Management's Discussion and Analysis of Financial Condition
and Results of Operations(1).......................................................... 11
Item 7A - Quantitative and Qualitative Disclosures about Market Risk(1)............................... 11
Item 8 - Financial Statements and Supplementary Data(1).............................................. 11
Item 9 - Changes in and Disagreements with Accountants on Accounting
and Financial Disclosure(2)

PART III

Item 10 - Directors and Executive Officers of the Registrant(1)....................................... 11
Item 11 - Executive Compensation(1)................................................................... 12
Item 12 - Security Ownership of Certain Beneficial Owners
and Management(1)..................................................................... 12
Item 13 - Certain Relationships and Related Transactions(1)........................................... 12

PART IV

Item 14 - Exhibits, Financial Statement Schedules and Reports on Form 8-K............................. 12

SIGNATURES................................................................................................ 16
EXHIBITS.................................................................................................. 17

- ---------------------
(1) Incorporated herein by reference.
(2) Not applicable and not included herein.

PART I

ITEM 1. BUSINESS.

GENERAL

The Registrant, Ameren Corporation (Ameren or the Company), was
incorporated in Missouri on August 7, 1995. On December 31, 1997, following the
receipt of all required approvals, CIPSCO Incorporated (CIPSCO) and Union
Electric Company (AmerenUE) combined with the result that the common
shareholders of CIPSCO and AmerenUE became the common shareholders of the
Company, and the Company became the owner of 100% of the common stock of
AmerenUE and CIPSCO's utility operating subsidiary, Central Illinois Public
Service Company (AmerenCIPS) (the Merger).

For additional information about the Merger, see "Overview" in
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" and Notes 1 and 2 to the "Notes to Consolidated Financial
Statements" on Pages 15, 28, and 29, respectively, of the 1999 Annual Report
pages incorporated herein by reference.

Ameren is a public utility holding company registered under the
Public Utility Holding Company Act of 1935 (PUHCA) and does not own or operate
any significant assets other than the stock of its subsidiaries, including its
two utility operating subsidiaries, AmerenCIPS and AmerenUE. Dividends on
Ameren's Common Stock are dependent on distributions to be made to it by
AmerenCIPS, AmerenUE, and its other subsidiaries. The 1999 Annual Reports Form
10-K for AmerenCIPS and AmerenUE are available from the Company upon request.

AmerenCIPS is an Illinois corporation organized in 1902. It
supplies electric and gas service to territories in central and southern
Illinois having an estimated population of 820,000 within an area of
approximately 20,000 square miles. AmerenUE was incorporated in Missouri in
1922, and is successor to a number of companies, the oldest of which was
organized in 1881. It is the largest electric utility in the State of Missouri
and supplies electric and gas service in territories in Missouri and Illinois
having an estimated population of 2,600,000 within an area of approximately
24,500 square miles, including the greater St. Louis area.

On a consolidated basis, 93.3% of the Company's 1999 operating
revenues were derived from the sale of electric energy, 6.5% came from the sale
of natural gas, and 0.2% came from other sources. Consolidated electric
operating revenues as a percentage of total operating revenues for the years
1998 and 1997 were 93.3% and 92%, respectively.

The Company also owns all of the common stock of other subsidiary
companies as follows: (a) CIPSCO Investment Company, a nonregulated investment
company incorporated in Illinois; (b) Ameren Services Company, a Missouri
corporation which provides administrative, accounting, legal, engineering,
executive, and other support services to Ameren and all of its subsidiaries; (c)
AmerenEnergy, Inc., a Missouri corporation which primarily serves as a power
marketing agent for the operating utility companies and provides a range of
energy and risk management services to targeted customers; (d) Ameren
Development Company, a nonregulated holding company incorporated in Missouri
encompassing Ameren's nonregulated products and services; and (e) Ameren Energy
Resources Company (until March 2000, known as Ameren Intermediate Holding Co.,
Inc.), a nonregulated Illinois holding company for an Illinois nonregulated
generating subsidiary (Ameren Energy Generating Company) and its marketing
affiliate (Ameren Energy Marketing Company) scheduled to be operational in May
2000. In addition, through its operating subsidiaries, the Company owns 60% of
the Common Stock of Electric Energy, Inc., which owns and operates a generating
plant with a nominal capacity of 1,000 mW. Of the plant's total output, 50% is
committed to the Department of Energy, 15% to AmerenUE, 7.5% to AmerenCIPS, and
the remainder to its other owners.

1
4

At December 31, 1999, the Company and its subsidiaries had 7,347
employees. Approximately 70% of such employees are represented by local unions
affiliated with the AFL-CIO. New contracts with collective bargaining units
representing approximately 60% of these employees were ratified in 1999 with
terms expiring in 2002. Labor agreements which expired in 1999 have not been
renewed with International Brotherhood of Electrical Workers (IBEW) Locals 1439,
309, 649 and 1455, who collectively represent approximately 2,000 employees.
Negotiations with Local 1455 are still ongoing. However, after engaging in
extensive good-faith bargaining with IBEW Locals 1439, 309 and 649, the Company
submitted a last, best and final offer to these collective bargaining units on
February 2, 2000. The offer was rejected and the Company informed these locals
that it would implement the noneconomic portion of its offer effective March 6,
2000. The employees are currently working under the noneconomic portion of the
Company's last, best and final offer. The Company is unable to predict what
further action, if any, these collective bargaining units will take or the
response of the Company's other union represented employees to any action by its
employees. The Company is also unable to determine what, if any, impact these
labor matters could have on its future financial condition, results of
operations or liquidity. For more information on labor agreements and other
labor matters, see Note 12 to the "Notes to Consolidated Financial Statements"
on Page 38 of the 1999 Annual Report pages incorporated herein by reference.

For additional information regarding the Company's business
operations, see "Regulation" section below and "Management's Discussion and
Analysis" on Pages 15-22 and the Consolidated Financial Information on Pages
23-45 of the 1999 Annual Report pages incorporated herein by reference.

CAPITAL PROGRAM AND FINANCING

The Company is engaged in a capital program under which capital
expenditures are expected to approximate $749 million in 2000. During 1999, the
Company committed to purchase combustion turbine generators which will add more
than 2,700 megawatts to its net peaking capacity and are expected to cost
approximately $1.2 billion. Except for nearly 200 megawatts, the new capacity is
expected to be operated by Ameren Energy Generating Company, the new Illinois
nonregulated generating subsidiary. For the five-year period 2000 through 2004,
construction expenditures are estimated at $3.3 billion. This estimate includes
capital expenditures for the purchase of the new combustion turbine generators,
as well as expenditures that will be incurred by the Company to meet new air
quality standards for ozone and particulate matter.

In addition to the funds required for construction during the
2000-2004 period, $897 million will be required to repay long-term debt as
follows: $129 million in 2000; $45 million in 2001; $275 million in 2002; $160
million in 2003; and $288 million in 2004. Amounts for years subsequent to 2000
do not include AmerenUE's nuclear fuel lease payments since the amounts of such
payments are not currently determinable.

To issue first mortgage bonds and preferred stock, AmerenCIPS and
AmerenUE each must comply with earnings tests contained in their respective
mortgages and Articles of Incorporation. For the issuance of additional first
mortgage bonds, generally, earnings coverage of twice the annual interest
charges on first mortgage bonds outstanding and to be issued is required.
Generally, for the issuance of additional preferred stock, earnings coverage of
one and one-half times annual interest charges and preferred stock dividends is
required under the AmerenCIPS Articles, and earnings coverage of at least two
and one-half times the annual dividend on preferred stock outstanding and to be
issued is required under AmerenUE's Articles. The ability to issue such
securities in the future will depend on coverages at that time. Currently, each
company expects to have adequate coverage ratios for anticipated requirements.

For additional information on the Company's capital program and
financial needs, see "Liquidity and Capital Resources" in "Management's
Discussion and Analysis of Financial Condition

2
5

and Results of Operations" on Page 17, and Notes 5, 7, 8, and 12 to the "Notes
to Consolidated Financial Statements" on Pages 32, 33, 34 and 38, of the 1999
Annual Report pages incorporated herein by reference.

RATES

For the year 1999, approximately 61%, 23%, and 16% of the
Company's electric operating revenues were based on rates regulated by the
Missouri Public Service Commission (MoPSC), the Illinois Commerce Commission
(ICC), and the Federal Energy Regulatory Commission (FERC) of the U. S.
Department of Energy, respectively. For information on rate matters in these
jurisdictions, see "Electric Industry Restructuring" in "Management's Discussion
and Analysis of Financial Condition and Results of Operations" and Note 2 to the
"Notes to Consolidated Financial Statements" on Pages 19 and 29, respectively,
of the 1999 Annual Report pages incorporated herein by reference.

Reference is being made to Note 2 (Missouri Electric) to the
"Notes to Consolidated Financial Statements" on Page 29 of the 1999 Annual
Report pages incorporated herein by reference for a discussion of the December
1999 Report and Order (Order) of the MoPSC relating to or impacting customer
credits under AmerenUE's original and new experimental electric alternative
regulation plans. On February 24, 2000, AmerenUE filed a Petition for Writ of
Review with the Circuit Court of Cole County, Missouri asking that the MoPSC's
Order be reversed. AmerenUE has also requested that the court issue a stay of
the Order. While it is unable to predict the ultimate outcome of the judicial
appeal of the MoPSC's Order, Ameren believes that the final decision will not
have a material adverse effect on its financial position, results of operations
or liquidity.

Further reference is being made to Note 2 (Illinois Electric
Restructuring) to the "Notes to Consolidated Financial Statements" for a
discussion of the August 1999 order of the ICC approving the delivery service
tariffs filed by AmerenUE and AmerenCIPS and the rehearing of that order granted
by the ICC on certain issues. The ICC issued an order in 2000 on this reopened
proceeding resolving all outstanding issues.

In February 2000, AmerenUE filed a request with the MoPSC to
increase rates approximately $12 million annually for natural gas service in its
Missouri jurisdiction. The MoPSC has until January 2001 to render a decision.

FUEL SUPPLY

COST OF FUELS YEAR
- ------------- ------------------------------------------------------------------------------
1999 1998 1997 1996 1995
---- ---- ---- ---- ----

AMERENUE
- --------
Per Million BTU - Coal 100.685(cent) 100.015(cent) 105.600(cent) 112.250(cent) 117.645(cent)
- Nuclear 46.552(cent) 48.803(cent) 47.472(cent) 47.499(cent) 48.592(cent)
- System 89.833(cent) 90.378(cent) 92.816(cent) 96.596(cent) 101.590(cent)

AMERENCIPS
- ----------
Per Million BTU - System (Coal) 139.700(cent) 152.738(cent) 163.000(cent) 171.000(cent) 176.000(cent)

OIL. The actual and prospective use of such fuel is minimal, and
the Company has not experienced and does not expect to experience difficulty in
obtaining adequate supplies.

GAS. The combustion turbine generators which the Company has
committed to purchase (see "Capital Program and Financing" section above) will
be fueled by natural gas. Consequently, the prospective use of natural gas to
supply such facilities is expected to increase significantly. The Company does
not expect to experience difficulty in obtaining adequate supplies to support
the new generation facilities.

3
6

COAL. Because of uncertainties of supply due to potential work
stoppages, equipment breakdowns and other factors, the Company has a policy of
maintaining a coal inventory consistent with its expected burn practices.

NUCLEAR. The components of the nuclear fuel cycle required for
nuclear generating units are as follows: (1) uranium; (2) conversion of uranium
into uranium hexafluoride; (3) enrichment of uranium hexafluoride; (4)
conversion of enriched uranium hexafluoride into uranium dioxide and the
fabrication into nuclear fuel assemblies; and (5) disposal and/or reprocessing
of spent nuclear fuel.

The Company has agreements and/or inventories to fulfill its
Callaway Nuclear Plant needs for uranium, enrichment, fabrication and conversion
services through 2002. Additional contracts will have to be entered into in
order to supply nuclear fuel during the remainder of the life of the Plant, at
prices which cannot now be accurately predicted. The Callaway Plant normally
requires refueling at 18-month intervals, with the next regular refueling
presently scheduled for the spring of 2001.

Under the Nuclear Waste Policy Act of 1982, the U. S. Department
of Energy (DOE) is responsible for the permanent storage and disposal of spent
nuclear fuel. DOE currently charges one mill per nuclear generated kilowatt-hour
sold for future disposal of spent fuel. Electric rates charged to customers
provide for recovery of such costs. DOE is not expected to have its permanent
storage facility for spent fuel available until at least 2015. The Company has
sufficient storage capacity at the Callaway site until 2020 and has the
capability for additional storage capacity through the licensed life of the
plant in 2024. The delayed availability of the DOE's disposal facility is not
expected to adversely affect the continued operation of Callaway Plant.

For additional information on the Company's "Fuel Supply", see
"Results of Operations" in "Management's Discussion and Analysis of Financial
Condition and Results of Operations" and Notes 12 and 13 to the "Notes to
Consolidated Financial Statements" on Pages 15, 38 and 41, respectively, of the
1999 Annual Report pages incorporated herein by reference.

REGULATION

As a holding company registered under the PUHCA, Ameren, along
with its subsidiaries, is subject to the regulatory provisions of said Act,
including provisions relating to the issuance of securities, sales and
acquisitions of securities and utility assets, the services performed by Ameren
Services Company, and the activities of certain other subsidiaries.

AmerenCIPS and AmerenUE are subject to regulation, as applicable,
by the MoPSC and the ICC as to rates, service, accounts, issuance of equity
securities, issuance of debt having a maturity of more than twelve months,
mergers, and various other matters. Said companies are also subject to
regulation by the FERC as to rates and charges in connection with the
transmission of electric energy in interstate commerce and the sale of such
energy at wholesale in interstate commerce, mergers, and certain other matters.
Authorization to issue debt having a maturity of twelve months or less is
obtained from the Securities and Exchange Commission.

For information on regulatory matters in these jurisdictions,
including the current status of electric utility restructuring in Illinois and
Missouri, see "Electric Industry Restructuring" in "Management's Discussion and
Analysis of Financial Condition and Results of Operations" and Note 2 to the
"Notes to Consolidated Financial Statements" on Pages 19 and 29, respectively,
of the 1999 Annual Report pages incorporated herein by reference.

Reference is being made to "Electric Industry Restructuring" in
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" and Note 2 (Illinois Electric Restructuring) to the "Notes to
Consolidated Financial Statements" on Pages 19 and 29, respectively, of the 1999
Annual Report pages incorporated herein by reference, for a discussion of
AmerenCIPS' transfer of its

generating facilities to a new nonregulated subsidiary of Ameren. In conjunction
with Illinois' Electric Service Customer Choice and Rate Relief Law of 1997, in
July 1999, AmerenCIPS filed a notice with the ICC that it intends to transfer
AmerenCIPS' generating facilities (all in Illinois) to a new nonregulated
subsidiary of the Company. The formation of the new generating subsidiary, as
well as the transfer of AmerenCIPS' generating assets and liabilities (at
historical net book value of approximately $600 million) and certain power sales
contracts, was subject to various regulatory approvals from the ICC, the FERC,
and the MoPSC, all of which have been received as of March 10, 2000. An
additional PUHCA-related determination that will permit the new generating
subsidiary to operate as an Exempt Wholesale Generator is being sought from the
FERC. The generating subsidiary (Ameren Energy Generating Company) will include
most of the new combustion turbine generators being acquired by the Company, in
addition to the AmerenCIPS facilities. The new generating subsidiary is expected
to be operational in May 2000. The proposed transfer of AmerenCIPS' generating
assets and liabilities had no effect on the Company's financial statements as of
December 31, 1999.

Operation of the Company's Callaway Plant is subject to
regulation by the Nuclear Regulatory Commission. Its Facility Operating License
for the Callaway Plant expires on October 18, 2024. The Company's Osage
hydroelectric plant and its Taum Sauk pumped-storage hydro plant, as licensed
projects under the Federal Power Act, are subject to FERC regulations affecting,
among other things, the general operation and maintenance of the projects. The
license for the Osage Plant expires on February 28, 2006, and the license for
the Taum Sauk Plant expires on June 30, 2010. The Company's Keokuk Plant and dam
located in the Mississippi River between Hamilton, Illinois and Keokuk, Iowa,
are operated under authority, unlimited in time, granted by an Act of Congress
in 1905.

Ameren and its subsidiaries are regulated, in certain of their
operations, by air and water pollution and hazardous waste regulations at the
city, county, state and federal levels. These companies are in substantial
compliance with existing regulations.

ENVIRONMENTAL ISSUES. On December 22, 1995, a complaint was filed
in the Circuit Court for the Seventh Judicial Circuit, Sangamon County, Illinois
against AmerenCIPS and several other defendants. The complaint sought
unspecified monetary damages and alleged that, as a result of exposure to
carcinogens contained in coal tar at the AmerenCIPS Taylorville gas plant site,
plaintiffs' children had suffered from a rare form of childhood cancer known as
"neuroblastoma". In 1998, a jury awarded plaintiffs $3.2 million. In March 2000,
the Illinois Appellate Court, on an appeal by AmerenCIPS, upheld the plaintiffs'
verdict. AmerenCIPS plans to seek an appeal of the court's decision to the
Illinois Supreme Court. The Company believes that final disposition of this
matter will not have a material adverse effect on the financial position,
results of operations or liquidity of the Company.

On August 2, 1996, the Illinois Attorney General filed a
complaint with the Illinois Pollution Control Board alleging various violations
of wastewater discharge permit conditions and ground water standards at
AmerenCIPS' Hutsonville Power Station. The complaint seeks monetary penalties
and the award of attorney fees. AmerenCIPS, the Illinois Environmental
Protection Agency and the Attorney General have reached a settlement in
principle resolving the complaint which will require the Company to perform
remedial actions at the site. Any final settlement of this matter must be
approved by the Illinois Pollution Control Board. While the Company cannot
predict the final outcome of this matter, it does not believe that the final
resolution will have a material adverse effect on financial position, results of
operations or liquidity of the Company.

For additional discussion of environmental matters, see
"Liquidity and Capital Resources" in Management's Discussion and Analysis of
Financial Condition and Results of Operations" and Note 12 to the "Notes to
Consolidated Financial Statements" on Pages 17 and 38, respectively, of the 1999
Annual Report pages incorporated by reference. Reference is being made to these
1999 Annual Report pages for a discussion of regulations issued by the United
States Environmental Protection Agency (EPA) to reduce NOx emissions from
coal-fired boilers and other sources in 22 states, including Missouri and
Illinois (where all of the Company's coal-fired power plant boilers are
located). In March 2000, the U.S. Court of Appeals for the District of Columbia
substantially upheld the proposed NOx regulations but remanded

portions of them to the EPA for further consideration. The implementation date
of the regulations is uncertain and further legal challenge is possible. The
Company is unable to predict the outcome of the litigation, the regulation
implementation date or the ultimate impact of these standards on its future
financial condition, results of operations or liquidity.

INDUSTRY ISSUES

The Company is facing issues common to the electric and gas
utility industries which have emerged during the past several years. These
issues include: the potential for more intense competition and for changing the
structure of regulation; changes in the structure of the industry as a result of
changes in federal and state laws, including the formation of unregulated
generating entities; on-going consideration of additional changes of the
industry by federal and state authorities; continually developing environmental
laws, regulations and issues, including proposed new air quality standards;
public concern about the siting of new facilities; proposals for demand side
management programs; public concerns about nuclear decommissioning and the
disposal of nuclear wastes; and global climate issues. The Company is monitoring
these issues and is unable to predict at this time what impact, if any, these
issues will have on its operations, financial condition, or liquidity.

Also see "Electric Industry Restructuring" in "Management's
Discussion and Analysis of Financial Condition and Results of Operations" and
Notes 2 and 12 to the "Notes to Consolidated Financial Statements" on Pages 19
and 38, respectively, of the 1999 Annual Report pages incorporated herein by
reference.

YEAR 2000 ISSUE. The Year 2000 Issue relates to how dates are
stored and used in computer systems, applications, and embedded systems. As the
century date change occurred, certain date-sensitive systems had to recognize
and properly treat the year as 2000 and not as 1900. This inability to recognize
and properly treat the year as 2000 could have caused these systems to process
critical financial and operational information incorrectly. The Company
encountered no significant problems associated with the Year 2000 Issue at
year-end. For additional information on this issue, see "Year 2000 Issue" in
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" on Page 20 of the 1999 Annual Report pages incorporated herein by
reference.

OPERATING STATISTICS

The information on Pages 44 and 45 in the Company's 1999 Annual
Report is incorporated herein by reference.

ITEM 2. PROPERTIES.

In planning its construction program, the Company is presently
utilizing a forecast of kilowatthour sales growth of approximately 2.0% and peak
load growth of 1.5%, each compounded annually, and is providing for a minimum
reserve margin of approximately 15% above its anticipated peak load
requirements.

The Company plans to add more than 2,700 megawatts to its net
peaking capacity with the purchase of combustion turbine generators (CTs). CTs
with a total capacity of approximately 590 megawatts are planned to be installed
in 2000, 560 megawatts in 2001, 590 megawatts in 2002, and 325 megawatts each in
2003 through 2005. For additional information, see Note 12 to the "Notes to
Consolidated Financial Statements" on Page 38 of the 1999 Annual Report pages
incorporated herein by reference.

The Company is a member of one of the ten regional electric
reliability councils organized for coordinating the planning and operation of
the nation's bulk power supply - MAIN (Mid-America

Interconnected Network) operating primarily in Wisconsin, Illinois and Missouri.
The Company's bulk power system is operated as an Ameren-wide control area and
transmission system under the FERC approved Joint Dispatch Agreement between
AmerenUE and AmerenCIPS. Ameren has interconnections for transmission service
and the exchange of electric energy, directly and through the facilities of
others, with more than twenty power suppliers.

The following table sets forth information with respect to the
Company's generating facilities and capability at the time of the expected 2000
peak.

GROSS KILOWATT
ENERGY INSTALLED
SOURCE PLANT LOCATION CAPABILITY
------ ----- -------- ----------

Coal Labadie Franklin County, MO 2,400,000
Rush Island Jefferson County, MO 1,224,000
Newton Newton, IL 1,170,000
Sioux St. Charles County, MO 1,006,000
Meramec St. Louis County, MO 859,000
Coffeen Coffeen, IL 950,000
Meredosia Meredosia, IL 359,000
Grand Tower Grand Tower, IL 202,000
Hutsonville Hutsonville, IL 161,000
------------

Total Coal 8,331,000

Nuclear Callaway Callaway County, MO 1,181,000

Hydro Osage Lakeside, MO 212,000
Keokuk Keokuk, IA 126,000
------------

Total Hydro 338,000

Oil and Venice Venice, IL 441,000
Natural Other Various 1,078,000*
-------------
Gas Total Oil and
Natural Gas 1,519,000
Pumped-
storage Taum Sauk Reynolds County, MO 440,000
------------

TOTAL 11,809,000
============

* Includes 517,000 gross kilowatt installed capability of new
combustion turbine generators scheduled for service before the
expected 2000 peak.

As of December 31, 1999, AmerenCIPS owned approximately 4,700
circuit miles of electric transmission lines. AmerenCIPS operates one
propane-air plant and 4,800 miles of gas mains. As of that date, AmerenUE owned
approximately 3,300 circuit miles of electric transmission lines. AmerenUE
operates three propane-air plants and 2,800 miles of gas mains. Other properties
of the companies include distribution lines, underground cable, office
buildings, warehouses, garages and repair shops.

Substantially all of the properties and plant of AmerenCIPS and
AmerenUE are subject to the direct first liens of the indentures securing their
first mortgage bonds. Pursuant to the Illinois electric restructuring
legislation enacted in December 1997 as the Electric Service Customer Choice and
Rate Relief Law of 1997, AmerenCIPS expects to transfer all of its generating
facilities and related assets to a new nonregulated generating subsidiary of
Ameren in May 2000. As a part of this transfer, AmerenCIPS' generating property
and plant will be released from the lien of the indenture securing its first
mortgage bonds. For additional information on this generating asset transfer,
see "Regulation" section under Item 1 herein and "Electric Industry
Restructuring" in "Management's Discussion and Analysis of Financial

Condition and Results of Operations" and Note 2 to the "Notes to Consolidated
Financial Statements" on Pages 19 and 30, respectively, of the 1999 Annual
Report pages incorporated herein by reference.

ITEM 3. LEGAL PROCEEDINGS.

The Company is involved in legal and administrative proceedings
before various courts and agencies with respect to matters arising in the
ordinary course of business, some of which involve substantial amounts. The
Company believes that the final disposition of these proceedings will not have a
material adverse effect on its financial position, results of operations or
liquidity.

For additional information on legal and administrative
proceedings, see "Rates" and "Regulation -- Environmental Issues" under Item 1
herein and "Electric Industry Restructuring" in "Management's Discussion and
Analysis of Financial Condition and Results of Operations" and Notes 2 and 12 to
the "Notes to Consolidated Financial Statements" on Pages 19, 29 and 38,
respectively, of the 1999 Annual Report pages incorporated herein by reference.

------------------

Statements made in this report which are not based on historical
facts, are "forward-looking" and, accordingly, involve risks and uncertainties
that could cause actual results to differ materially from those discussed.
Although such "forward-looking" statements have been made in good faith and are
based on reasonable assumptions, there is no assurance that the expected results
will be achieved. These statements include (without limitation) statements as to
future expectations, beliefs, plans, strategies, objectives, events, conditions,
financial performance and the Year 2000 Issue. In connection with the "Safe
Harbor" provisions of the Private Securities Litigation Reform Act of 1995, the
Company is providing this cautionary statement to identify important factors
that could cause actual results to differ materially from those anticipated. The
following factors, in addition to those discussed elsewhere in this report and
in subsequent securities filings, could cause results to differ materially from
management expectations as suggested by such "forward-looking" statements: the
effects of regulatory actions; changes in laws and other governmental actions;
the impact on the Company of current regulations related to the phasing-in of
the opportunity for some customers to choose alternative energy suppliers in
Illinois; the effects of increased competition in the future due to, among other
things, deregulation of certain aspects of the Company's business at both the
state and Federal levels; future market prices for fuel and purchased power,
electricity, and natural gas, including the use of financial instruments;
average rates for electricity in the Midwest; business and economic conditions;
interest rates; weather conditions; fuel prices and availability; generation
plant performance; the impact of current environmental regulations on utilities
and generating companies and the expectation that more stringent requirements
will be introduced over time, which could potentially have a negative financial
effect; monetary and fiscal policies; future wages and employee benefits costs;
and legal and administrative proceedings.

INFORMATION REGARDING EXECUTIVE OFFICERS REQUIRED BY ITEM 401(B) OF REGULATION
S-K:

DATE FIRST ELECTED
AGE AT OR APPOINTED TO
NAME 12/31/99 PRESENT POSITION PRESENT POSITION
---- -------- ---------------- ----------------

Ameren Corporation
- ------------------

Charles W. Mueller 61 Chairman, President and
Chief Executive Officer,
and Director 12/31/97
Donald E. Brandt 45 Senior Vice President 12/31/97
Steven R. Sullivan 39 Vice President, General Counsel 7/1/98
and Secretary 9/1/98
Warner L. Baxter 38 Vice President 5/1/98
and Controller 12/31/97
Jerre E. Birdsong 45 Treasurer 4/23/96

AmerenUE (Subsidiary)
- ---------------------

Charles W. Mueller 61 President, 7/1/93
Chief Executive Officer 1/1/94
and Director 6/11/93
Donald E. Brandt 45 Senior Vice President 7/1/88
and Director 4/28/98
Daniel F. Cole 46 Senior Vice President 7/12/99
Thomas F. Voss 52 Senior Vice President 6/1/99
Warner L. Baxter 38 Vice President, 5/1/98
Controller and 8/1/96
Director 4/22/99
William J. Carr 62 Vice President 10/1/88
Michael J. Montana 53 Vice President 7/1/88
Charles D. Naslund 47 Vice President 2/1/99
Garry L. Randolph 51 Vice President 3/1/91
William C. Shores 61 Vice President 7/1/88
Steven R. Sullivan 39 Vice President, General Counsel 7/1/98
and Secretary 9/1/98
Jerre E. Birdsong 45 Treasurer 7/1/93

AmerenCIPS (Subsidiary)
- -----------------------

Gary L. Rainwater 53 President,
Chief Executive Officer 1/1/98
and Director 12/31/97
Thomas R. Voss 52 Senior Vice President 6/1/99
Warner L. Baxter 38 Vice President, 4/22/99
Controller and 12/31/97
Director 4/22/99
Michael J. Montana 53 Vice President 4/28/98
Gilbert W. Moorman 56 Vice President 6/1/88
Craig D. Nelson 46 Vice President 4/28/98
Jerry L. Simpson 43 Vice President 6/1/99
Steven R. Sullivan 39 Vice President, General Counsel
and Secretary 11/7/98
Jerre E. Birdsong 45 Treasurer 12/31/97

9
12

INFORMATION REGARDING EXECUTIVE OFFICERS REQUIRED BY ITEM 401(B) OF REGULATION
S-K:

DATE FIRST ELECTED
AGE AT OR APPOINTED TO
NAME 12/31/99 PRESENT POSITION PRESENT POSITION
---- -------- ---------------- ----------------

Ameren Services Company (Subsidiary)
- ------------------------------------

Charles W. Mueller 61 President, Chief Executive
Officer and Director 11/4/97
Paul A. Agathen 52 Senior Vice President 12/31/97
and Director 4/27/99
Donald E. Brandt 45 Senior Vice President 12/31/97
and Director 11/4/97
Daniel F. Cole 46 Senior Vice President 6/1/99
Thomas F. Voss 52 Senior Vice President 6/1/99
Warner L. Baxter 38 Vice President 4/28/98
and Controller 12/31/97
Charles A. Bremer 55 Vice President 12/31/97
Donald W. Capone 64 Vice President 12/31/97
William J. Carr 62 Vice President 7/7/99
J. L. Davis 52 Vice President 12/31/97
Jean M. Hannis 52 Vice President 12/31/97
R. Alan Kelley 47 Vice President 12/31/97
Michael J. Montana 53 Vice President 12/31/97
Craig D. Nelson 46 Vice President 12/31/97
Gregory L. Nelson 42 Vice President 2/16/99
J. Kay Smith 54 Vice President 7/1/99
Steven R. Sullivan 39 Vice President, General Counsel 7/1/98
and Secretary 9/1/98
Samuel E. Willis 55 Vice President 12/31/97
Ronald C. Zdellar 55 Vice President 12/31/97
Jerre E. Birdsong 45 Treasurer 12/31/97

All officers are elected or appointed annually by the respective
Board of Directors of such company following the election of such Board at the
annual meetings of stockholders held in April. There are no family relationships
between the foregoing officers of the Company. Except for Messrs. Baxter,
Gregory L. Nelson and Sullivan, each of the above-named executive officers has
been employed by the Company or its affiliates for more than five years in
executive or management positions. Mr. Baxter was previously employed by
PricewaterhouseCoopers LLP. Mr. Nelson was previously employed by the law firm
of Thelen Reid & Priest LLP. Mr. Sullivan was previously employed by Anheuser
Busch Companies, Inc.

PART II

ITEM 5. MARKET FOR REGISTRANT'S COMMON EQUITY AND RELATED STOCKHOLDER
MATTERS.

On October 9, 1998, the Company adopted a Shareholder Rights Plan
and declared a dividend of one preferred share purchase right (a Right) for each
outstanding share of common stock, par value $ .01 per share, of the Company.
Each Right entitles the registered holder to purchase from the Company one
one-hundredth of a share of Series A Junior Participating Preferred Stock, par
value $ .01 per share, of the Company at a price of $180 per one one-hundredth
of a share of such Preferred Stock, subject to adjustment. The Rights will
become exercisable if someone buys 15 percent or more of the

Company's common stock. In addition, if someone buys 15 percent or more of the
Company's common stock, each right will entitle its holder (other than that
buyer) to purchase a number of shares of the Company's common stock having a
market value of twice the Right's $180 exercise price. If the Company is
acquired in a merger, each Right will entitle its holder to purchase a number of
the acquiring company's common shares having a market value at the time of twice
the Right's exercise price.

The Rights will expire on October 9, 2008. The Rights do not have
voting or dividend rights, and until they become exercisable, have no dilutive
effect on the per-share earnings of the Company. The Company has 4 million
shares of Preferred Stock initially reserved for issuance upon exercise of the
Rights. There is no Junior Participating Preferred Stock issued or outstanding.

For additional information on the Shareholder Rights Plan, see
Note 6 to the "Notes to Consolidated Financial Statements" on Page 33 of the
1999 Annual Report pages incorporated herein by reference.

Additional information required to be reported by this item is
included on the inside back cover of the 1999 Annual Report and is incorporated
herein by reference.

ITEM 6. SELECTED FINANCIAL DATA.

Information for the 1994-1999 period required to be reported by
this item is included on Page 43 of the 1999 Annual Report and is incorporated
herein by reference.

ITEM 7. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
RESULTS OF OPERATIONS.

Information required to be reported by this item is included on
Pages 15 through 22 of the 1999 Annual Report and is incorporated herein by
reference.

ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK.

Information required to be reported by this item is included under
"Market Risk Related to Financial Instruments and Commodity Instruments" in
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" on Page 21 of the 1999 Annual Report and is incorporated herein by
reference.

ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA.

The financial statements of the Company on Pages 23 through 42,
the report thereon of PricewaterhouseCoopers LLP appearing on Page 14 and the
Selected Quarterly Information on Page 27 of the 1999 Annual Report are
incorporated herein by reference.

PART III

ITEM 10. DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT.

Information concerning directors required to be reported by this
item is included under "Item (1): Election of Directors" in the Company's 2000
definitive proxy statement filed pursuant to Regulation 14A and is incorporated
herein by reference.

Information concerning executive officers required by this item is
reported in Part I of this Form 10-K.

ITEM 11. EXECUTIVE COMPENSATION.

Any information required to be reported by this item is included
under "Compensation" in the Company's 2000 definitive proxy statement filed
pursuant to Regulation 14A and is incorporated herein by reference.

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT.

Any information required to be reported by this item is included
under "Security Ownership of Management" in the Company's 2000 definitive proxy
statement filed pursuant to Regulation 14A and is incorporated herein by
reference.

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS.

Any information required to be reported by this item is included
under "Item (1): Election of Directors" in the Company's 2000 definitive proxy
statement filed pursuant to Regulation 14A and is incorporated herein by
reference.

PART IV

ITEM 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULES, AND REPORTS ON FORM 8-K.

(a) The following documents are filed as a part of this report:

1. Financial Statements: *

Page From 1999
Annual Report
-------------

Consolidated Report of Independent Accountants.................................. 14
Consolidated Statement of Income - Years 1999, 1998, and 1997................... 23
Consolidated Balance Sheet - December 31, 1999 and 1998......................... 24
Consolidated Statement of Cash Flows - Years 1999, 1998, and 1997............... 26
Consolidated Statement of Retained Earnings
- Years 1999, 1998, and 1997................................................. 27
Notes to Consolidated Financial Statements...................................... 28

* Incorporated by reference from the indicated pages of the
1999 Annual Report

2. Financial Statement Schedule:

The following schedule, for the years ended December 31, 1999,
1998 and 1997, should be read in conjunction with the
aforementioned financial statements (schedules not included have
been omitted because they are not applicable or the required data
is shown in the aforementioned financial statements).

Pages Herein
------------

Report of Independent Accountants on Financial
Statement Schedule........................................................... 14

Valuation and Qualifying Accounts (Schedule II)................................. 15

3. Exhibits: See EXHIBITS beginning on Page 17

(b) Reports on Form 8-K. The Company filed a report on Form 8-K dated
December 20, 1999 reporting AmerenCIPS' termination of coal supply
contracts, the resulting estimated pretax fuel cost savings and
the recording of a nonrecurring charge. Further, a report dated
January 20, 2000 was filed reporting the issuance of a Report and
Order dated December 23, 1999 by the Missouri Public Service
Commission regarding AmerenUE's electric alternative regulation
plans.

13
16

REPORT OF INDEPENDENT ACCOUNTANTS
ON FINANCIAL STATEMENT SCHEDULE

To the Board of Directors
of Ameren Corporation

Our audits of the financial statements referred to in our report dated February
2, 2000 appearing in the 1999 Annual Report to Shareholders of Ameren
Corporation (which report and financial statements are incorporated by reference
in this Annual Report on Form 10-K) also included an audit of the Financial
Statement Schedule listed in Item 14(a)(2) of this Form 10-K. In our opinion,
this Financial Statement Schedule presents fairly, in all material respects, the
information set forth therein when read in conjunction with the related
financial statements.

/s/ PricewaterhouseCoopers LLP

PricewaterhouseCoopers LLP
St. Louis, Missouri
February 2, 2000

14
17

AMEREN CORPORATION
SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS
FOR THE YEARS ENDED DECEMBER 31, 1999, 1998 AND 1997

Col. A Col. B Col. C Col. D Col. E
------ ------ ------ ------ ------

Additions
---------------------------------
(1) (2)
Balance at Charged to Balance at
beginning costs and Charged to end of
Description of period expenses other accounts Deductions period
----------- --------- -------- -------------- ---------- ------
(Note)

Year ended December 31, 1999

Reserves deducted in the balance sheet from
assets to which they apply:

Allowance for doubtful accounts $8,392,655 $12,240,000 $13,496,315 $7,136,340
========== =========== =========== ==========

Year ended December 31, 1998

Reserves deducted in the balance sheet from
assets to which they apply:

Allowance for doubtful accounts $4,845,328 $21,167,000 $17,619,673 $8,392,655
========== =========== =========== ==========

Year ended December 31, 1997

Reserves deducted in the balance sheet from
assets to which they apply:

Allowance for doubtful accounts $5,795,332 $12,648,812 $13,598,816 $4,845,328
========== =========== =========== ==========

Note: Uncollectible accounts charged off, less recoveries.

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the
Securities Exchange Act of 1934, the registrant has duly caused this report to
be signed on its behalf by the undersigned, thereunto duly authorized.

AMEREN CORPORATION
(Registrant)

CHARLES W. MUELLER
Chairman, President and
Chief Executive Officer

Date March 29, 2000 By /s/ Steven R. Sullivan
--------------- --------------------------
(Steven R. Sullivan, Attorney-in-Fact)

Pursuant to the requirements of the Securities Exchange Act of 1934,
this report has been signed below by the following persons on behalf of the
registrant and in the capacities and on the date indicated.

SIGNATURE TITLE
--------- -----

/s/ C. W. Mueller Chairman, President, Chief
- -------------------------------------------------- Executive Officer and Director
CHARLES W. MUELLER (Principal Executive Officer)

/s/ Donald E. Brandt Senior Vice President
- -------------------------------------------------- (Principal Financial Officer)
DONALD E. BRANDT

/s/ Warner L. Baxter Vice President and Controller
- -------------------------------------------------- (Principal Accounting Officer)
WARNER L. BAXTER

/s/ William E. Cornelius
- --------------------------------------------------
WILLIAM E. CORNELIUS, Director

/s/ Clifford L. Greenwalt
- -------------------------------------------------- ------------------------------------------------
CLIFFORD L. GREENWALT, Director HANNE M. MERRIMAN, Director

/s/ Thomas A. Hays /s/ Paul L. Miller, Jr.
- -------------------------------------------------- ------------------------------------------------
THOMAS A. HAYS, Director PAUL L. MILLER, JR., Director

/s/ Richard A. Liddy /s/ Robert H. Quenon
- -------------------------------------------------- ------------------------------------------------
RICHARD A. LIDDY, Director ROBERT H. QUENON, Director

/s/ Gordon R. Lohman /s/ Harvey Saligman
- -------------------------------------------------- ------------------------------------------------
GORDON R. LOHMAN, Director HARVEY SALIGMAN, Director

/s/ Richard A. Lumpkin /s/ Janet McAfee Weakley
- -------------------------------------------------- ------------------------------------------------
RICHARD A. LUMPKIN, Director JANET McAFEE WEAKLEY, Director

/s/ John Peters MacCarthy
- -------------------------------------------------- ------------------------------------------------
JOHN PETERS MacCARTHY, Director JAMES W. WOGSLAND, Director

By /s/ Steven R. Sullivan March 29, 2000
-------------------------------------------
(Steven R. Sullivan, Attorney-in Fact)

EXHIBITS

EXHIBITS FILED HEREWITH
-----------------------

EXHIBIT NO. DESCRIPTION
- ----------- -----------

13 - Those pages of the 1999 Annual Report incorporated herein by
reference.

21 - Subsidiaries of the Company.

23 - Consent of Independent Accountants.

24 - Powers of Attorney.

27 - Financial Data Schedule.

EXHIBITS INCORPORATED BY REFERENCE
----------------------------------

The following exhibits heretofore have been filed with the
Securities and Exchange Commission pursuant to requirements of the Acts
administered by the Commission. Such exhibits are identified by the references
following the listing of each such exhibit, and they are hereby incorporated
herein by reference.

EXHIBIT NO. DESCRIPTION
- ----------- -----------

2 - Agreement and Plan of Merger, dated as of August 11, 1995, by and
among the Company, CIPSCO Incorporated, UE, and Arch Merger Inc.
(June 30, 1995 Form 10-Q/A (Amendment No. 1), Exhibit 2(a).)

3(i) - Restated Articles of Incorporation of the Company. (Registration
No. 33-64165, Annex F.)

3(ii) - Certificate of Amendment to the Restated Articles of Incorporation
filed with the Secretary of State of the State of Missouri on
December 14, 1998. (1998 Form 10-K, Exhibit 3(i).)

3(iii) - By-Laws of the Company as amended to December 31, 1997. (1997 Form
10-K, Exhibit 3(ii).)

4.1 - Indenture of Mortgage and Deed of Trust of Union Electric Company
dated June 15, 1937, as amended May 1, 1941, and Second Supplemental
Indenture dated May 1, 1941. (Registration No. 2-4940, Exhibit B-1.)

EXHIBIT NO. DESCRIPTION
- ----------- -----------

4.2 - Supplemental Indentures to the Union Electric Company Mortgage

DATED AS OF FILE REFERENCE EXHIBIT NO.
----------- -------------- -----------
March 1, 1967 2-58274 2.9
April 1, 1971 Form 8-K, April 1971 6
February 1, 1974 Form 8-K, February 1974 3
July 7, 1980 2-69821 4.6
May 1, 1990 Form 10-K, 1990 4.6
December 1, 1991 33-45008 4.4
December 4, 1991 33-45008 4.5
January 1, 1992 Form 10-K, 1991 4.6
October 1, 1992 Form 10-K, 1992 4.6
December 1, 1992 Form 10-K, 1992 4.7
February 1, 1993 Form 10-K, 1992 4.8
May 1, 1993 Form 10-K, 1993 4.6
August 1, 1993 Form 10-K, 1993 4.7
October 1, 1993 Form 10-K, 1993 4.8
January 1, 1994 Form 10-K, 1993 4.9
December 1, 1996 Form 10-K, 1996 4.36

4.3 - Indenture of Mortgage or Deed of Trust dated October 1,
1941, from CIPS to Continental Illinois National Bank and
Trust Company of Chicago and Edmond B. Stofft, as Trustees.
(Exhibit 2.01 in File No. 2-60232.)

4.4 - Supplemental Indentures dated, respectively September 1,
1947, January 1, 1949, February 1, 1952, September 1, 1952,
June 1, 1954, February 1, 1958, January 1, 1959, May 1,
1963, May 1, 1964, June 1, 1965, May 1, 1967, April 1, 1970,
April 1, 1971, September 1, 1971, May 1, 1972, December 1,
1973, March 1, 1974, April 1, 1975, October 1, 1976,
November 1, 1976, October 1, 1978, August 1, 1979, February
1, 1980, February 1, 1986, May 15, 1992, July 1, 1992,
September 15, 1992, April 1, 1993, and June 1, 1995 between
CIPS and the Trustees under the Indenture of Mortgage or
Deed of Trust referred to above (Amended Exhibit 7(b) in
File No. 2-7341; Second Amended Exhibit 7.03 in File No.
2-7795; Second Amended Exhibit 4.07 in File No. 2-9353;
Amended Exhibit 4.05 in file No. 2-9802; Amended Exhibit
4.02 in File No. 2-10944; Amended Exhibit 2.02 in File No.
2-13866; Amended Exhibit 2.02 in File No. 2-14656; Amended
Exhibit 2.02 in File No.2-21345; Amended Exhibit 2.02 in
File No. 2-22326; Amended Exhibit 2.02 in File No. 2-23569;
Amended Exhibit 2.02 in File No. 2-26284; Amended Exhibit
2.02 in File No. 2-36388; Amended Exhibit 2.02 in File No.
2-39587; Amended Exhibit 2.02 in File No. 2-41468; Amended
Exhibit 2.02 in File No. 2-43912; Exhibit 2.03 in File No.
2-60232; Amended Exhibit 2.02 in File No. 2-50146; Amended
Exhibit 2.02 in File No. 2-52886; Second Amended Exhibit
2.04 in File No. 2-57141; Amended Exhibit 2.04 in File No.
2-57557; Amended Exhibit 2.06 in File No. 2-62564; Exhibit
2.02(a) in File No. 2-65914; Amended Exhibit 2.02(a) in File
No. 2-66380; and Amended Exhibit 4.02 in File No. 33-3188;
Exhibit 4.02 to Form 8-K dated May 15, 1992; Exhibit 4.02 to
Form 8-K dated July 1, 1992; Exhibit 4.02 to Form 8-K dated
September 15, 1992; Exhibit 4.02 to Form 8-K dated March 30,
1993; Exhibit 4.03 to Form 8-K dated June 5, 1995; Exhibit
4.03 to Form 8-K dated March 15, 1997; Exhibit 4.03 to Form
8-K dated June 1, 1997; and Exhibit 4.02, Post-Effective
Amendment No. 1 in File No. 333-18473.)

EXHIBIT NO. DESCRIPTION
- ----------- -----------

4.5 - Agreement, dated as of October 9, 1998, between the Company and First Chicago Trust
Company of New York, as Rights Agent, which includes the form of Certificate of Designation
of the Preferred Shares as Exhibit A, the form of Right Certificate as Exhibit B and the Summary
of Rights as Exhibit C. (October 14, 1998 Form 8-K, Exhibit 4.)

4.6 - Indenture dated as of December 1, 1998 from CIPS to the Bank of New York relating to CIPS'
Senior Notes, 5.375% due 2008 and 6.125% due 2028. (Exhibit 4.03, Post-Effective Amendment No. 1
to File No. 333-18473.)

10.1 - Long-Term Incentive Plan of 1998. (1998 Form 10-K, Exhibit 10.1.)

10.2 - Change of Control Severance Plan. (1998 Form 10-K, Exhibit 10.2.)

10.3 - Deferred Compensation Plan for Members of the Ameren Leadership Team. (1998 Form 10-K, Exhibit
10.3.)

10.4 - Deferred Compensation Plan for Members of the Board of Directors. (1998 Form 10-K, Exhibit 10.4.)

Note: Reports of Union Electric Company on Forms 8-K, 10-Q and 10-K are on file
with the SEC under File Number 1-2967.

Reports of Central Illinois Public Service Company on Forms 8-K, 10-Q and
Form 10-K are on file with the SEC under File Number 1-3672.