Hollywood had one of its best summers ever at the domestic box office, but it was a sharply lopsided victory. Studios either thrived or withered, an outcome that reflects the winner-take-all nature of the mass-appeal movie business.

Ticket sales at North American cinemas rose an estimated 10.4 percent, to $4.48 billion, for the period between the first weekend in May and Labor Day, from the same period a year earlier, the analytics firm Rentrak said on Sunday. Hollywood’s summer, which was one week longer this year because of a calendar quirk, has historically accounted for up to 40 percent of annual domestic ticket sales.

But the strong season was overwhelmingly owing to movies supplied by just two of Hollywood’s six major studios. Twelve movies took in more than $100 million in the United States and Canada, and eight of them were from Universal Pictures, a division of Comcast’s NBCUniversal, and Walt Disney Studios. Together, Universal and Disney controlled 60 percent of the market, Rentrak said.