Baltimore-based energy company Constellation’s plans to acquire a Houston, Texas-based natural gas producer in a $26.6 billion deal will boost the nation’s biggest energy firm right as

Constellation Energy Corp. shares surged to a record high after agreeing to acquire closely held Calpine Corp. for $16.4 billion in a deal that will create the largest fleet of US power stations.

Constellation Energy Corporation CEG and Calpine Corp. announced that they have entered into a definitive agreement under which CEG will acquire Calpine in a cash and stock transaction valued at an equity purchase price of nearly $16.