1. Ameren Rates and Regulation Wilbon L. Cooper Manager Rate Engineering Ameren Services Company A.F.E. Meeting- - April 29, 2003

2. WHO WE ARE: Ameren’s Utility Operations AmerenCIPs - Gas & Electric (IL) AmerenCILCO – Gas & Electric (IL) AmerenUE – Gas and Electric (MO & IL)

3. Key Financial Data (2002): Electric Customers1,700,000 Gas Customers 500,000 Generating Capacity 14,500 MW Electric System Miles 56,500 Total Assets$13.4 Billion Total Operating Revenues$4,623 Million Note: Includes AmerenCILCO Data

5. HISTORY OF MISSOURI RETAIL RATES

6. MO RATE CASE SETTLEMENT Three (3) Year Phase In Decrease Year 1- 50,000,000 Reduction (April 1, 2002) Year 2 – $30,000,000 Reduction (April 1, 2003) Year 3 – $30,000,000 Reduction (April 1, 2004) Total Reduction - $110,000,000

7. Percentage Reductions by Major Rate Class Associated with MO Electric Rate Reduction AprilAprilApril 200220032004 Residential-2.5%-1.4% -1.4% Small General Service-3.0%-1.9% -1.9% Large General Service-2.5%-1.4% -1.4% Small Primary Service-2.5%-1.4% -1.4% Large Primary Service-4.4%-3.3% -3.3% Total-2.7%-1.6% -1.6%

8. CURRENT RATES: Residential – Customer Charge$7.25 (All months) - Energy Charges Summer (Billing Periods Of June-September) 7.77 cents per kWh Winter (Billing Periods of October-May) First 750 kWh @5.51 cents per kWh Over 750 kWh @3.72 cents per kWh Small General Service – Customer Charge Single Phase$7.25 (All months) Three Phase $15.10 (All months) - Energy Charges Summer (Billing Periods Of June-September) 7.58 cents per kWh Winter (Billing Periods of October-May) Base kWh @5.65 cents per kWh Seasonal kWh @3.27 cents per kWh

9. CURRENT RATES (Cont’d): Large General ServiceSmall Primary Service Customer Charge$66.00 (All months)$210.00 (All months) Summer (Billing Periods Of June-September) Energy Charges - per kWh First 150 kWh per kW of Billing Demand7.52 cents 7.15 cents Next 200 kWh per kW of Billing Demand5.67 cents 5.40 cents Over 350kWh per kW of Billing Demand3.80 cents 3.61 cents Demand Charge $3.64 $2.89 Large General Service Small Primary Service Customer Charge$66.00 (All months)$210.00 (All months) Winter (Billing Periods Of June-September) Energy Charges - kWh First 150 kWh per kW of Billing Demand4.71 cents 4.50 cents Next 200 kWh per kW of Billing Demand3.53 cents3.35 cents Over 350kWh per kW of Billing Demand2.74 cents2.62 cents Seasonal Energy Charge2.74 cents2.62 cents Demand Charge – per kW of Billing Demand$1.30$1.06

10. CURRENT RATES (Cont’d): Large Primary Service Rate Customer Charge$210.00 (All months) Summer (Billing Periods Of June-September) Energy Charge - per kWh2.42 cents Demand Charge – per kW of Billing Demand $14.48 per kW Reactive Charge - per kVar24 cents Winter (Billing Periods Of October -May) Energy Charge - per kWh2.13 cents Demand Charge – per kW of Billing Demand $6.57 per kW Reactive Charge - per kVar24 cents

11. DeregulationILLINOIS ACTIVE SINCE 1998 MISSOURI NO CURRENT LEGISLATIVE ACTIVITY

12. Ameren Contact for Rate Information: Mr. Wil Cooper Manager – Rate Engineering Ameren Services Company 314-554-3248 (Phone) 314-554-4679 (Fax) wilbon_l_cooper@ameren.com