Ameren Corp. has completed the merger of its three Illinois electric and natural gas utilities – AmerenCIPS, AmerenCILCO and AmerenIP – into a single public utility now known as "Ameren Illinois."

The reorganization has been approved by the Federal Energy Regulatory Commission and the appropriate notice was filed in the spring of 2010 with the Illinois Commerce Commission.

The legal name for the combined utility is Ameren Illinois Company, and it is a direct subsidiary of Ameren Corporation. In addition, AmerenUE, which serves approximately 1.2 million customers in Missouri, today began doing business as "Ameren Missouri."

The reorganization of the Illinois utilities does not affect the current customer electricity and natural gas rates.

"This merger is the logical next step in the evolution of our business in Illinois," said Thomas R. Voss, chairman, president and chief executive officer of Ameren Corp. "For the last several years, we have been moving towards operating our Illinois utilities as one company to reduce the cost of operations and gain efficiencies for our customers.

"We also want to communicate clearly with our customers and, for that reason, with the completion of this merger we are announcing name changes for our operations in both Illinois and Missouri," Voss added. "Since the utility companies in Illinois and Missouri operate under different regulatory requirements and business models, we believe we are adding clarity for all our stakeholders by identifying each of our utility companies by the state in which it does business.

"These changes make it clear that each utility is focused on the needs of its customers – helping us differentiate the pricing structures and rates and services offered, based on regulatory and legislative differences."

In Illinois, the merger and related synergies also are expected to provide greater convenience for customers, such as a single "800" toll-free telephone number for use in reporting outages or obtaining account information. In addition, the merger is expected to reduce confusion among customers who formerly received bills from two of the Illinois utilities and in shared media markets in areas that border both Illinois and Missouri.

"With this merger, we expect to benefit from economies of scale and realize operating efficiencies from reductions in the administrative work associated with maintaining three utilities," said Ameren Illinois chairman, president and chief executive officer Scott A. Cisel. "This merger will enable us to become more efficient, enhance customer satisfaction and support our commitment to provide safe, reliable electricity and natural gas delivery service."

Communication about the merger has been and will be handled directly with customers through bill inserts and through news media releases. Signage with these new names will be phased in over time to avoid unnecessary costs.

Subsequent to the consummation of the Merger, Ameren Illinois distributed all of the shares of common stock of AmerenEnergy Resources Generating Company owned by Ameren Illinois to Ameren Corporation, and Ameren Corporation subsequently contributed such shares of common stock to its subsidiary, Ameren Energy Resources Company LLC.

Headquartered in Peoria, Ill., Ameren Illinois serves all or part of 85 of Illinois' 102 counties and ranks as the second largest Illinois electricity delivery operation in total number of customers (approximately 1.2 million). Ameren Illinois also ranks as the third largest Illinois natural gas distribution operation in total number of customers (approximately 813,000) and operates 45,000 miles of electric distribution lines and 18,000 miles of natural gas distribution and transmission mains.

With assets of $24 billion, Ameren serves approximately 2.4 million electric customers and almost one million natural gas customers in a 64,000-square-mile area of Missouri and Illinois. Ameren owns a diverse mix of electric generating plants strategically located in its Midwest market with a generating capacity of 16,900 megawatts.