The following discussion should be read in conjunction with the financial statements contained in this Form 10-Q as well as Management's Discussion and Analysis of Financial Condition and Results of Operations and Risk Factors contained in the Form 10-K. We intend for this discussion to provide the reader with information that will assist in understanding our financial statements, the changes in certain key items in those financial statements, and the primary factors that accounted for those changes, as well as how certain accounting principles affect our financial statements. The discussion also provides information about the financial results of the various segments of our business to provide a better understanding of how those segments and their results affect the financial condition and results of operations of Ameren as a whole.

OVERVIEW

Ameren Executive Summary

Ameren's earnings in the first quarter of 2009 of $141 million, or $0.66 per share, were comparable with its earnings in the first quarter of 2008 of $138 million, or $0.66 per share. First quarter earnings in 2009 were favorably impacted by unrealized MTM activity on derivatives and the benefit to earnings of new utility service rates in Illinois, effective October 1, 2008, and in Missouri, effective March 1, 2009, among other positive factors. Offsetting these factors in the first quarter of 2009 were lower electric and gas sales volumes, higher fuel and related transportation prices, the impact of a severe winter ice storm, and the effect of seasonal gas delivery service rate redesign for the Ameren Illinois Utilities.

Milder weather and the absence of a leap day in 2009 contributed to a 6% decline in kilowatthour sales to residential customers and a 2% decline in kilowatthour sales to commercial customers. Absent these factors, we estimate that first quarter 2009 residential and commercial kilowatthour sales each declined 1% versus the year-ago period. The weak economy significantly impacted industrial electric sales. Industrial sales declined 13% from the year-ago quarter, excluding the impact of a storm-related loss of operating capacity at UE's largest customer, Noranda. While this industrial decline was significant, sales to these customers represented only 16% of UE's and only 6% of the Ameren Illinois Utilities' native load electric revenues in 2008. In addition, such sales are relatively low margin.

With respect to operations, UE's equivalent availability for its coal-fired generating units was 90% in the first quarter of 2009, which was comparable to the first quarter 2008 level. However, UE's Callaway nuclear plant experienced a 12-day unplanned outage in the first quarter of 2009. Non-rate-regulated Generation's equivalent availability for its coal-fired units was 81% for the first quarter of 2009 compared with 85% in the same year-ago period. This decline reflects a planned outage to complete installation of a multi-pollutant control system and major maintenance at its Duck Creek power plant. This planned outage, as well as lower market prices for power and reduced generation at another of its plants due to MISO system transmission congestion issues, resulted in a decline in generation output. While Non-rate-regulated Generation's volumes were down in the quarter, its electric margin was only down slightly due to proactive physical sales and financial hedges of 2009 generation made in prior years at higher-than-current market prices.

UE had been investing in a nuclear COLA and heavy forgings for a possible second nuclear unit at its existing Callaway site to preserve a nuclear generation option for meeting its customers' future energy needs toward the end of the next decade. In April 2009, UE suspended those efforts because proposed legislation in the Missouri General Assembly that would have allowed utilities to recover financing costs from customers while building a new plant had been stripped of the provisions UE needed to move forward. UE will consider all available and feasible generation options to meet future customer requirements as part of an updated integrated resource plan that UE is due to file with the MoPSC in June 2010. In the meantime, UE is assessing all options to maximize the value of its investment in this project.

CILCORP recognized a goodwill impairment loss of $462 million during the first quarter of 2009 due to a significant decline in Ameren's market capitalization, the continuing decline in market prices for electricity, and a decrease in observable industry market multiples. CILCORP's impairment charge did not result in a goodwill impairment charge at the consolidated Ameren level. However, the estimated fair values of Ameren's Illinois Regulated reporting unit, Ameren's Non-rate-regulated Generation reporting unit, and IP's Illinois Regulated reporting unit exceeded their carrying value by a nominal amount as of March 31, 2009. As a result, the failure in the future of any reporting unit to achieve forecasted operating results and cash flows or a further decline of observable industry market multiples may reduce its estimated fair value below its carrying value and would likely result in the recognition of a goodwill impairment charge. We will continue to monitor the actual and forecasted operating results, cash flows, market capitalization, market prices for electricity, and observable industry market multiples of these reporting units for signs of possible declines in estimated fair value and potential goodwill impairment.

Outlook

The global capital and credit markets experienced extreme volatility and disruption in 2008 and early 2009, and we expect those conditions to continue throughout the rest of 2009 and potentially longer. The current weak economic conditions will likely result in weaker power and commodity markets, greater risk of defaults by our counterparties, weaker customer sales growth, particularly with respect to industrial sales, higher bad debt expense, higher financing costs, and possible impairment of goodwill and long-lived assets, among other things.

Future initiatives regarding greenhouse gas emissions and global warming are subject to active consideration in the U.S. Congress. In March 2009, the U.S. House of Representatives Committee on Energy and Commerce, Subcommittee on Energy and the Environment, issued a draft energy bill that included climate legislation. The climate legislation proposes establishing an economy-wide cap-and-trade program. The overarching goal of such legislation is to reduce greenhouse gas emissions to a level that is 20%

below 2005 levels by 2020, 42% below 2005 levels by 2030, and 83% below 2005 levels by the year 2050. The draft legislation also contains a renewable energy standard of 25% by the year 2025 and an energy efficiency mandate for electric and gas utilities, as well as other requirements. President Obama supports an economy-wide cap-and-trade greenhouse gas reduction program that would reduce emissions to 14% below 2005 levels by 2020 and to 80% below 2005 levels by 2050. President Obama has also indicated support for auctioning 100% of the emission allowances to be distributed under the legislation. However, recent statements from the Obama administration indicate a willingness to support some level of emission allowance allocation. Although we cannot predict the date of enactment or the requirements of any climate legislation, it is likely that some form of federal climate legislation will become law during the Obama administration. Potential impacts from proposed legislation could vary, depending upon proposed CO2 emission limits, the timing of implementation of those limits, the method of allocating allowances, and provisions for cost containment measures.

General

Ameren, headquartered in St. Louis, Missouri, is a public utility holding company under PUHCA 2005 administered by FERC. Ameren's primary assets are the common stock of its subsidiaries. Ameren's subsidiaries are separate, independent legal entities with separate businesses, assets and liabilities. These subsidiaries operate rate-regulated electric generation, transmission and distribution businesses, rate-regulated natural gas transmission and distribution businesses, and non-rate-regulated electric generation businesses in Missouri and Illinois. Dividends on Ameren's common stock and the payment of other expenses by the Ameren and CILCORP holding companies are dependent on distributions made to it by its subsidiaries. Ameren's principal subsidiaries are listed below.

• UE operates a rate-regulated electric generation, transmission and distribution business, and a rate-regulated natural gas transmission and distribution business in Missouri.

• CIPS operates a rate-regulated electric and natural gas transmission and distribution business in Illinois.

• Genco operates a non-rate-regulated electric generation business in Illinois and Missouri.

• CILCO, a subsidiary of CILCORP (a holding company), operates a rate-regulated electric and natural gas transmission and distribution business and a non-rate-regulated electric generation business (through its subsidiary, AERG) in Illinois.

• IP operates a rate-regulated electric and natural gas transmission and distribution business in Illinois.

In addition to presenting results of operations and earnings amounts in total, we present certain information in cents per share. These amounts reflect factors that directly affect Ameren's earnings. We believe this per share information helps readers to understand the impact of these factors on Ameren's earnings per share. All references in this report to earnings per share are based on average diluted common shares outstanding during the applicable period. All tabular dollar amounts are in millions, unless otherwise indicated.

RESULTS OF OPERATIONS

Earnings Summary

Our results of operations and financial position are affected by many factors. Weather, economic conditions, and the actions of key customers or competitors can significantly affect the demand for our services. Our results are also affected by seasonal fluctuations: winter heating and summer cooling demands. The vast majority of Ameren's revenues are subject to state or federal regulation. This regulation has a material impact on the price we charge for our services. Non-rate-regulated Generation sales are also subject to market conditions for power. We principally use coal, nuclear fuel, natural gas, and oil for fuel in our operations. The prices for these commodities can fluctuate significantly due to the global economic and political environment, weather, supply and demand, and many other factors. We have natural gas cost recovery mechanisms for our Illinois and Missouri gas delivery businesses and purchased power cost recovery mechanisms for our Illinois electric delivery businesses. As part of the electric rate order issued by the MoPSC in January 2009, UE was granted permission to put in place a FAC, which was effective March 1, 2009. Fluctuations in interest rates and conditions in the capital and credit markets affect our cost of borrowing and our pension and postretirement benefits costs. We employ various risk management strategies to reduce our exposure to commodity risk and other risks inherent in our business. The reliability of our power plants and transmission and distribution systems, the level of purchased power costs, operating and administrative costs, and capital investment are key factors that we seek to control to optimize our results of operations, financial position, and liquidity.

Net income attributable to Ameren Corporation increased to $141 million, or 66 cents per share, in the first quarter of 2009, from $138 million, or 66 cents per share, in the first quarter of 2008. Net income attributable to Ameren Corporation in the first quarter of 2009 increased in the Illinois Regulated and Non-rate-regulated Generation segments by $9 million and $15 million, respectively, from the prior-year period, while net income attributable to Ameren Corporation in the Missouri Regulated segment declined by $31 million from the same period in 2008.

Earnings were favorably impacted in the first quarter of 2009 as compared with the same period in 2008 by:

• higher electric and natural gas delivery service rates in the Illinois Regulated segment pursuant to the ICC consolidated rate order for CIPS, CILCO, and IP issued in September 2008 (12 cents per share);

• favorable net unrealized MTM activity on energy-related transactions (9 cents per share);

• higher electric rates in the Missouri Regulated segment pursuant to the MoPSC rate order issued in January 2009 (3 cents per share);

• higher electric margins at our non-rate-regulated generation businesses (3 cents per share);

• decreased bad debt expenses (2 cents per share); and

• decreased plant operations and maintenance expense (2 cents per share).

Earnings were negatively impacted in the first quarter of 2009 as compared with the same period in 2008 by:

• lower electric and gas margins at our rate-regulated businesses, excluding impacts of the rate increases noted above (17 cents per share);

• the implementation of redesigned gas delivery service rates at the Ameren Illinois Utilities, which impacts quarterly earnings comparison but is not expected to have a material impact on annual margins (5 cents per share);

• higher financing costs (4 cents per share);

• reduced sales to Noranda due to a severe storm-related outage (3 cents per share); and

• unfavorable weather conditions (estimated at 3 cents per share).

The cents per share information presented above is based on average shares outstanding in the first quarter of 2008.

Because it is a holding company, net income attributable to Ameren Corporation and cash flows are primarily generated by its principal subsidiaries: UE, CIPS, Genco, CILCORP and IP. The following table presents the contribution by Ameren's principal subsidiaries to net income attributable to Ameren Corporation for the three months ended March 31, 2009 and 2008:

                                                           Three Months
                                                         2009         2008
        Net income (loss):
        UE                                              $   21        $  63 (a)
        CIPS                                                 6            2
        Genco                                               47           46
        CILCORP                                           (432 )(b)      20
        IP                                                  13            2
        Other(c)                                           486 (b)        5
        Net income attributable to Ameren Corporation   $  141        $ 138

(a) Includes earnings from a non-rate-regulated 40% interest in EEI through February 29, 2008.

(b) Includes goodwill impairment loss of $462 million offset by intercompany elimination in Other as no impairment was recognized at the consolidated Ameren level. See Note 14 - Goodwill Impairment to our financial statements under Part I, Item 1, of this report for additional information.

(c) Includes earnings from EEI, other non-rate-regulated operations, as well as corporate general and administrative expenses, and intercompany eliminations. Includes a 40% interest in EEI prior to February 29, 2008, and an 80% interest in EEI since that date.

Below is a table of income statement components by segment for the three months ended March 31, 2009 and 2008:

                                                                       Non-rate-            Other /
                                   Missouri          Illinois          regulated         Intersegment
                                   Regulated         Regulated         Generation        Eliminations        Total
Three Months 2009:
Electric margin                   $       411       $       193       $        287       $          (3 )     $  888
Gas margin                                 27               111                  -                   -          138
Other revenues                              1                 4                  -                  (5 )          -
Other operations and
maintenance                              (216 )            (136 )              (78 )                 9         (421 )
Depreciation and amortization             (86 )             (53 )              (28 )                (7 )       (174 )
Taxes other than income taxes             (62 )             (39 )               (7 )                (2 )       (110 )
Other income and (expenses)                11                 1                  -                   -           12
Interest expense                          (53 )             (41 )              (25 )                 1         (118 )
Income taxes                              (11 )             (14 )              (54 )                 9          (70 )
Net income (loss)                          22                26                 95                   2          145
Noncontrolling interest and
preferred dividends                        (1 )              (1 )               (2 )                 -           (4 )
Net income (loss)
attributable to Ameren
Corporation                                21                25                 93                   2          141
Three Months 2008:
Electric margin                   $       441       $       178       $        274       $         (13 )     $  880
Gas margin                                 28               125                  -                   -          153

                                                                     Non-rate-            Other /
                               Missouri           Illinois           regulated          Intersegment
                               Regulated          Regulated          Generation         Eliminations           Total
Other operations and
maintenance                          (217 )             (147 )               (79 )                13               (430 )
Depreciation and
amortization                          (81 )              (55 )               (27 )                (6 )             (169 )
Taxes other than income
taxes                                 (60 )              (43 )                (8 )                (2 )             (113 )
Other income and
(expenses)                             12                  4                  (1 )                 -                 15
Interest expense                      (41 )              (35 )               (21 )                (3 )             (100 )
Income taxes                          (29 )               (9 )               (52 )                 3                (87 )
Net income (loss)                      53                 18                  86                  (8 )              149
Noncontrolling interest
and preferred dividends                (1 )               (2 )                (8 )                 -                (11 )
Net income (loss)
attributable to Ameren
Corporation                            52                 16                  78                  (8 )              138

Margins

The following table presents the favorable (unfavorable) variations in the registrants' electric and gas margins for the three months ended March 31, 2009, compared with the same period in 2008. Electric margins are defined as electric revenues less fuel and purchased power costs. Gas margins are defined as gas revenues less gas purchased for resale. We consider electric, interchange, and gas margins useful measures to analyze the change in profitability of our electric and gas operations between periods. We have included the analysis below as a complement to the financial information we provide in accordance with GAAP. However, these margins may not be a presentation defined under GAAP and may not be comparable to other companies' presentations or more useful than the GAAP information we provide elsewhere in this report.

Three Months                         Ameren(a)          UE            CIPS            Genco          CILCORP         CILCO            IP
Electric revenue change:
Effect of weather (estimate)        $       (12 )    $     (11 )    $      (1 )    $         -      $       -      $       -      $        -
Regulated rates:
Changes in base rates                        36             11              5                -             (1 )           (1 )            21
FAC (over-recovery)                         (13 )          (13 )            -                -              -              -               -
Illinois pass-through power
costs                                       (34 )            -            (14 )              -            (17 )          (17 )            (3 )
Non-rate-regulated Generation
sales price changes                           6              -              -               26             12             12               -
Off-system revenues                         (21 )          (21 )            -                -              -              -               -
Illinois settlement agreement,
net of reimbursement                          5              -              1                2              1              1               1
Net MTM gains                                29              4              -                -              -              -               -
Noranda sales                               (13 )          (13 )            -                -              -              -               -
Generation output and other                 (57 )          (19 )           (6 )            (36 )          (19 )          (19 )            (5 )
Total electric revenue change       $       (74 )    $     (62 )    $     (15 )    $        (8 )    $     (24 )    $     (24 )    $       14
Fuel and purchased power change:
Fuel:
Generation and other                $        23      $     (15 )    $       -      $        24      $       7      $       6      $        -
Net MTM gains (losses)                       28             38              -               (6 )           (1 )           (1 )             -
Price                                       (23 )          (11 )            -               (6 )            -              -               -
Purchased power                              20             20              3                -             14             14               1
Illinois pass-through power
costs                                        34              -             14                -             17             17               3
Total fuel and purchased power
change                              $        82      $      32      $      17      $        12      $      37      $      36      $        4
Net change in electric margins      $         8      $     (30 )    $       2      $         4      $      13      $      12      $       18
Gas margin change:
Effect of weather (estimate)        $        (4 )    $       -      $      (1 )    $         -      $      (1 )    $      (1 )    $       (2 )
Gas rate increases                           13              -              3                -             (4 )           (4 )            14
Illinois seasonal rate redesign             (17 )            -             (4 )              -             (4 )           (4 )            (9 )
Other                                        (7 )           (1 )           (3 )              -              1              1              (4 )
Net change in gas margins           $       (15 )    $      (1 )    $      (5 )    $         -      $      (8 )    $      (8 )    $       (1 )

(a) Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

Ameren

Ameren's electric margin increased by $8 million, or 1%, for the three months ended March 31, 2009, compared with the same period in 2008. The following items had a favorable impact on electric margin:

• The reversal and deferral as regulatory assets of previously recorded UE net MTM losses on energy and fuel-related transactions of $42 million.

• The effect of rate increases. The Ameren Illinois Utilities' net electric rate increase, effective October 1, 2008, which increased electric margin by $25 million. The UE electric rate increase, effective March 1, 2009, which increased electric margin by $11 million.

• The repricing of wholesale and retail electric power supply agreements and financial swaps settling at higher margins at Non-rate-regulated Generation.

• The reduced impact of the Illinois electric settlement agreement, which increased electric margin by $5 million.

• Increased electric margin of $5 million related to the recovery of costs to administer the Ameren Illinois Utilities' power supply responsibilities. This primarily relates to the increase in the Supply Cost Adjustment (SCA) factors approved in the 2008 ICC electric rate order.

The following items had an unfavorable impact on electric margin:

• Fuel prices increased by 4%.

• Off-system sales revenues at UE decreased by $21 million due primarily to a 23% decrease in realized sales prices.

• Reduced sales to Noranda due to a severe storm-related outage, which lowered electric margin by $10 million. See Outlook for further information on the Noranda plant outage.

• Unfavorable weather conditions, as evidenced by a 7% reduction in heating degree-days, which decreased electric margin by an estimated $6 million.

• Excluding sales to Noranda, the impact of the economic slowdown, as evidenced by a 5% decrease in weather-normalized sales volumes, which decreased electric margin by $17 million. Specifically, combined commercial and industrial sales volumes decreased by 7%.

• The implementation of the FAC at UE, effective March 1, 2009. UE's base rates reflect costs set in the January 2009 MoPSC electric rate order for fuel and purchased power costs, net of off-system revenues. UE records 95% of the difference between actual net fuel costs and the base net fuel costs included in retail rates as an increase to or a reduction of electric revenues and defers such amount as a regulatory asset or liability to be recovered from or refunded to UE's retail customers. In the first quarter of 2009, UE's electric revenues were reduced by $13 million as a result of an over-recovery of fuel and purchased power costs, net of off-system sales.

• Decreased power plant utilization due to lower demand and system transmission congestion. Ameren's baseload coal-fired generating plants' equivalent availability and capacity factors were 87% and 75%, respectively, in the first quarter of 2009 compared with 86% and 80%, respectively, in the first quarter of 2008.

• Increased net MTM losses primarily at the Non-rate-regulated Generation segment on fuel-related transactions of $10 million, primarily related to financial instruments that were acquired to mitigate the risk of rising diesel fuel price adjustments embedded in coal transportation contracts for the period 2009 through 2012.

• Reduced Callaway nuclear plant availability due to a 12-day unplanned outage, which decreased electric margin by an estimated $7 million.

Ameren's gas margin decreased by $15 million, or 10%, for the three months ended . . .