JEFFERSON CITY—To reflect estimated changes in the wholesale cost of natural
gas, Union Electric Company d/b/a Ameren Missouri natural gas customers will see natural
gas rates drop under a filing that takes effect on May 1, 2015.  

Ameren Missouri residential customers in all of its service areas will see natural gas
rates decrease by approximately $0.12 per Ccf (per hundred cubic feet of natural gas).    

Approximately 55% to 60% of a customer’s current natural gas bill reflects the cost
of natural gas from wholesale suppliers.  The wholesale cost of natural gas (the cost your
local natural gas company must pay to its suppliers for natural gas) is not regulated by the
Missouri Public Service Commission.  The wellhead cost of natural gas is unregulated and is
primarily driven by supply, demand and the weather.  The Missouri Public Service
Commission does conduct an annual regulatory review to ensure that regulated natural gas
companies make prudent decisions in securing natural gas supplies for their customers. 

Ameren Missouri serves approximately 127,300 natural gas customers in Missouri.