The confirmation of the $7.9 billion deal by shareholders was widely expected by analysts, but had its critics. Federal and state regulatory reviews are still required for the deal, which company officials say is on track to close in the first quarter of next year.
More than three-quarters of Constellation's shareholders submitted votes on the deal; the special shareholders' meeting took place in New York City. Constellation said that 87 percent of the votes were in favor of the merger.
Ninety-seven percent of the Exelon shareholders who voted were in favor of the combination. Exelon's shareholder meeting occurred in Chicago.
Constellation's second-largest shareholder and nuclear partner, French utility EDF, said it would vote against the proposed merger. EDF has a 7.2 percent stake in Constellation.
EDF is also opposing the transaction during regulatory review before the Maryland Public Service Commission. The PSC is expected to make its decision on the deal on Jan. 5. Some state lawmakers have proposed that Constellation's regulated utility, Baltimore Gas & Electric Co., be excluded from the merger and remain an independent entity.
But Exelon officials have said they would only continue with the deal if BGE was included.
The deal also has to pass review by the Federal Energy Regulatory Commission, which earlier this week said it would delay its decision until possibly April.
The merger will lead to about 600 positions being cut across both companies, but the job reductions would be "most impactful" in Baltimore, affecting Constellation's legal, information technology, financial and other corporate departments, according to Exelon officials.