Baltimore-based Constellation, the nation’s largest operator of nuclear power plants, is acquiring Calpine Corp.

Baltimore-based Constellation is in discussions with Calpine’s private equity owners about the terms of a transaction that could value the company at about $30 billion including debt, according ...

Constellation Energy Corp. is nearing an acquisition of Calpine Corp., people familiar with the matter said, in what would be one of the biggest ever deals in the power generation sector.