Exelon Corporation (NYSE:EXC) and Constellation Energy (NYSE:CEG) today announced that they have completed their $11.2 bn merger.

The deal was announced last year but it has taken until today for all the required regulatory approvals to be granted.

The new company retains the Exelon name and remains headquartered in Chicago, with significant operations in Maryland, Illinois and Pennsylvania. It will trade on the New York Stock Exchange under the symbol EXC.

The merged company has around 100,000 business and public sector customers and approximately 1 million residential customers.

The three utilities within Exelon — BGE, ComEd and PECO — remain headquartered in Baltimore, Chicago and Philadelphia, respectively. Together, they serve 6.6 million gas and electric customers across three states.

The deal was the third biggest merger & acquisition of 2011 in the US, behind the 25.8bn merger of Progress Energy and Duke Energy and the $37.9bn deal involving El Paso Corp and Kinder Morgan.

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