New York (TheStreet) -- Aol CEO Tim Armstrong is looking to take his ad-tech investments mobile.

Purchased last month by Verizon (VZ) - Get Verizon Communications Inc. Report for $4.4 billion, Aol is reportedly in talks to acquire the mobile-advertising company Millennial Media (MM) . Al had been interested in Millennial Media before its acquisition by Verizon and could now make an offer between $300 million and $350 million, reportedTechCrunch, a site owned by Aol/Verizon.

Shares of Baltimore-based Millennial Media were surging 30% Thursday to $1.90. Verizon was slipping 0.6% to $46.31

"In many ways, Aol's strategy has been all about video and programmatic until now," Sorosh Tavakoli, senior vice president of ad-tech at the video data technology company Ooyala, said in a phone interview in New York. "This could be the start of the pushing toward mobile." 

The deal would demonstrate that Verizon has given Aol the green light to further expand its programmatic business to compete with other ad-tech companies as well asGoogle (GOOG) - Get Alphabet Inc. Class C Report and Facebook (FB) - Get Facebook, Inc. Class A Report, which account for roughly one-third of all digital ad-spending, according to eMarketer, an industry monitor.

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Aol's existing programmatic advertising investments were widely viewed as the main reason  Verizon acquired the New York-based company. Aol has been building out its mobile ad tech business for years, including the 2007 purchase of Third Screen Media. For the past three years, Aol's investments in automated advertising have exceeded $750 million.

The payoff has been handsome: sales related to programmatic accounted for 45% of overall brand advertising revenue in the three-month period ended March 31. In May, Aol's Armstrong said that "a fog is lifted off of Aol" since its investment in programmatic started paying off.

Aol, Tavakoli said, would be buying Millenial Media less for its programmatic technology than for the advantages of acquiring an experienced team of digital advertising executives with numerous existing contracts for ads on mobile devices.

"What they're buying more is the relationships [Millennial] has on the publisher and the advertising sides," said Tayakoli. "You're entering the mobile space not necessarily with scalable technology, but with all of that liquidity."

Mobile advertising is expected to account for 49% of all digital ad spending in 2015 and 72.2% by 2019, according to eMarketer. 

That's a far cry from its $2 billion valuation when the mobile ad startup went public in 2012. The company has since faced increasing consolidation in the mobile ad tech space as Google, Apple and Facebook snapped up similar properties.