Chicago-based Exelon is a step closer to becoming one of the largest power companies in the country. Shareholders of Exelon and its rival, Constellation Energy, approved a merger Thursday. Exelon is the parent company of Commonwealth Edison.

Analyst Travis Miller with Morningstar predicts the merger will bring new jobs to Illinois and benefit consumers. “You know a larger company offers cost savings that can flow to ComEd and reduce the infrastructure portion of consumer bills,” Miller said.

Miller predicts the merger will be finalized by early 2012, but it still needs approval from regulators.

Meantime, Illinois’ attorney general is criticizing the deal. Lisa Madigan’s office is concerned about what would happen to electricity prices if the merger goes through.