Duke Energy Corp , the largest power company in the United States, posted a 26 percent jump in quarterly net income on Thursday, helped by its summer buyout of rival Progress Energy.

For the third quarter, the company posted net income of $594 million, or 85 cents per share, compared with $472 million, or $1.06 per share, in the year-earlier period.

The company's total shares outstanding increased 57 percent between the periods, due in part to the Progress deal.

(Reporting By Ernest Scheyder; Editing by Gerald E. McCormick)