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NBCUniversal is close to a deal to invest $250 million in BuzzFeed, in a transaction that will value the booming digital publisher at around $1.5 billion.

Sources say Comcast’s TV and film unit has a “handshake” agreement with BuzzFeed, which raised $50 million last year at a $850 million valuation. NBCU also is negotiating to invest in Vox Media, which owns this website, in a deal that would value Vox at $850 million. Last fall Vox Media raised money at a $380 million valuation.

(Update: Sources said early BuzzFeed investors may also sell shares via secondary sales connected with the transaction.)

As in all dealmaking, these negotiations could fall apart. But sources said that both investments are close to being consummated.

People familiar with the proposed deals say they’re part of a new effort from NBCU CEO Steve Burke to bet on digital outlets he thinks can tap into millennial audiences, who are tuning out of NBCU’s TV networks and most others. The idea is that NBCU can get a crash course on digital content and distribution from its new investments — and that those companies may want to distribute some of NBCU’s content as well.

NBCUniversal, BuzzFeed and Vox Media declined to comment.

Last week, the Wall Street Journal reported that NBCUniversal was looking at multiple digital content outlets for potential investments or acquisitions.

BuzzFeed, which had previously considered selling to Disney, did more than $100 million in revenue last year. People familiar with the company say its internal projections called for revenue of $250 million this year, spurred in part by “native ads” created by its fast-growing video unit. That group, based in Los Angeles and run by Web 1.0 veteran Ze Frank, uses a factory-like model to create content that is consumed primarily in places other than BuzzFeed.com — like Facebook, YouTube and Snapchat.

BuzzFeed CEO Jonah Peretti wants to shift his whole company in that direction, and says he is intent on finding audiences for all of his content outside of BuzzFeed.com — which already attracts some 200 million visitors a month.

In the past few years there has been a flurry of investments in digital media companies, once thought to be toxic to investors. But the notion that these companies are the equivalent of cable TV networks like ESPN in the early 1980s — rough around the edges now, and incredibly valuable 10 and 20 years later — has become fashionable in some parts of the media world.

Example: Last year A&E, the cable programmer owned by Disney and Hearst, invested $250 million in Vice Media, in a deal that valued that company at $2.5 billion.

As part of the Vice/A&E deal, Vice is supposed to end up with its own cable network. A&E planned on handing over its H2 channel, a spin-off of its History channel, to Vice, which wanted to announce the new deal last spring. That transaction has been blocked, at least temporarily, by a distribution dispute with satellite TV network DirecTV.

BuzzFeed may also see the strategic value of linking up with NBCU, which owns a broadcast network, several cable channels and its own film studio.

While Peretti says that digital media will be his company’s focus, he has recently suggested that it may end up making traditional media, too. “Television and film are areas that could be initial places where we could experiment,” Peretti said at the Code Conference in May.