Exhibit 99.1
FORMULA FOR DETERMINING 2011 TARGET PERFORMANCE SHARE UNIT
AWARDS TO BE ISSUED TO NAMED EXECUTIVE OFFICERS
The target number of performance share units to be issued to each Named Executive Officer listed below for 2011 will be determined in accordance with the following formula:
2011 Target Number PSU Awards | = | Base Salary as of 1/1/11 | x | Long-Term Incentive Target listed below | ||||||||||||
Average closing price of Ameren Corporation Common Stock on The New York Stock Exchange for each trading day in December 2010 | ||||||||||||||||
NAMED EXECUTIVE OFFICER | LONG-TERM INCENTIVE TARGET AS PERCENT OF BASE SALARY | |||
| Voss | 315 | % | ||
| Lyons | 175 | % | ||
| Baxter | 175 | % | ||
| Sullivan | 160 | % | ||
| Naslund | 150 | % | ||
| Cisel | 150 | % | ||
