Cord cutting is accelerating as more people in the U.S. turn to Internet services such as Netflix, Hulu and YouTube to watch their favorite programs.

About 150,000 pay-TV customers canceled video service in the three months that ended June 30, according to estimates published on Friday by Leichtman Research Group.

Pay-TV systems lost 25,000 subscribers during the same time period last year, Leichtman said.

Sony, satellite-TV provider Dish Network and other companies have announced plans to start pay-TV systems that transmit channels over-the-Internet and offer smaller, less-expensive bundles. Sony and Dish said their aim is the attract younger consumers who have so far never signed up for traditional cable TV service.

Time Warner Cable lost the most with 182,000 defections, followed by Comcast with 81,000, according to Leichtman. Comcast, the biggest cable company in the U.S., is seeking permission from regulators to buy Time Warner Cable, the industry's second-biggest, for $45 billion.

AT&T, with its U-verse fiber-optic TV service, picked up the most subscribers with 216,000 new customers, Leichtman said. AT&T is seeking permission to buy satellite-TV provider DirecTV, which lost 28,000 subscribers, for $48.5 billion.

The 13 biggest pay-TV services in the U.S., which account for about 95% of the market, reach 95.3 million U.S. homes with a pay-TV service, according to Leichtman's estimates. That compares to the 115.6 million U.S. homes with at least one TV set, according to Nielsen.

Bruce Leichtman, president and principal analyst at the research company, expects the industry to reverse some of those losses and modestly add subscribers during the final three months of the year.