The Maryland Public Service Commission, a governing body similar to Pennsylvania's Public Utility Commission, announced the approval Friday with 40 conditions. Among them was that the resulting company creates a $113.5 million customer investment fund for energy efficiency and low-income energy assistance programs.

Last year, Chicago-based Exelon agreed to acquire Baltimore-based Constellation in a $7.9 billion all-stock deal that would make the new company the country's largest competitive energy provider. Both companies have approved the deal, as have regulatory agencies including the New York Public Service Commission, the Public Utility Commission of Texas, the U.S. Department of Justice and the Nuclear Regulatory Commission.

The companies still are seeking approval from the Federal Energy Regulatory Commission, according to Exelon.

Because the deal is happening at the corporate level, it does not require approval from the PUC, commission spokeswoman Jennifer Kocher said.

Exelon owns the Peach Bottom nuclear plant in York County and Three Mile Island nuclear plant in Dauphin County. The company trades its shares on the New York Stock Exchange under the ticker symbol EXC.

Constellation trades on the NYSE under the symbol CEG.