Hulu is going to lose some of the money it makes from ad sales to the three major media companies that control it. This comes less than a week after DirecTV and Time Warner Cable announced that they are looking to buy Hulu.

ABC, Fox and NBC have all been pushing for this. They want to take advantage of the new ways people sample videos on the streaming network.

Under a new agreement, ABC, Fox and NBC will retain control over up to 90 percent of the ads that come attached to the new episodes of shows from their respective networks that are streamed on the internet site. The new policy will probably go into effect starting with this fall’s new TV season.

This isn’t the first time that the streaming internet video company has clashed with the media conglomerate that owns it. Fox pushed the site to add more commercials to streams in 2011. That was good for News Corp. but went against the aesthetic that Hulu had built. Hulu usually runs less commercials than the networks do.

Hulu will continue to retain control of any ad sales that go along with old shows that have already been aired by ABC, NBC or Fox.

Hulu used to control the majority of ad sales that went along with current programs. Back in 2010, Jon Nesvig, former head of ad sales at Fox, said that Fox was able to buy Hulu ad time that it would then sell to its own sponsors. Not any more. Now the networks’ ad sales teams will become the lead for the series inventory.

Hulu will keep control of about 10% of the current-series inventory, which it will include in “run of site” ad packages that can be offered to sponsors. Hulu will represent the inventory that’s available in older series on Hulu that originally ran on a network.

Hulu expects to keep a “meaningful percentage” of the three networks’ ad inventory which will be sold by Hulu’s ad sales team.

The big change is getting little lip service from any of the players. A spokeswoman said Hulu executives declined to comment. ABC and NBC said executives were not available for comment. Fox was unable to respond to reporters.

Hulu is one of the most successful online video sites. They peaked in April with 4 million monthly premium subscribers in the first quarter. More than 1 billion videos were streamed in that period.

The Internet TV venture is owned by News Corp., Walt Disney Co. and Comcast’s NBCUniversal.