Over the years, FreeWheel has become the go-to ad-serving platform for many TV networks that stream their content online. And it’s about to become part of one of the biggest distributors of content online and off.

That’s because FreeWheel is about to be acquired by Comcast, our sources say. The deal, which should be announced soon, is rumored to be priced at around $320 million, according to one source. (UPDATE: A source close to the situation confirms the deal is nearly completed, but financial terms haven’t yet been finalized.)

FreeWheel is one of the largest platforms used by TV networks and major video distributors to serve ads alongside their content online. Since being founded in 2007, the company has racked up clients that include MLB.tv, ESPN, FOX, NBC Universal, Sky, Turner, and VEVO, among others.

Recently, it also signed up Amazon to begin serving ads alongside its streaming videos.

Comcast, of course, is interested in owning the technology for its own video ad platform. That said, FreeWheel is expected to continue serving outside clients, particularly the networks that the cable company has partnered with for its own TV Everywhere services.

An acquisition by Comcast might seem like a conflict of interest among some of FreeWheel’s customers — in particular satellite TV provider DirecTV, which is a competitor to Comcast and an investor in FreeWheel.

Then again, this wouldn’t be the first tech platform that Comcast has bought and run as a standalone subsidiary. In 2006 Comcast bought online video distribution startup thePlatform, which has continued to serve a number of cable providers and TV networks to deliver online streams of their content.

Other strategic investors in FreeWheel include Disney’s Steamboat Ventures and Turner Broadcasting System. The company had also raised institutional money from Battery Ventures and Foundation Capital over the years.

(As a side note, this is the second big win in recent months for Steamboat. It had also put early money into EdgeCast, which was acquired by Verizon for more than $350 million in December.)

The acquisition would also mark the latest exit for a company in the video ad world. Last summer, both YuMe and Tremor went public. Not long after, Adap.tv was acquired by TechCrunch parent company AOL. The last big video ad companies that are still private are LiveRail, which is targeting an IPO later this year, and BrightRoll.

Probably worth noting that while this is a big deal for FreeWheel, it’s a tiny acquisition for Comcast, which recently announced plans to buy Time Warner Cable for $45 billion.

We’ve reached out to Comcast and FreeWheel for comment and will update once we hear back.

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