(Bloomberg) -- French online advertising firm Criteo SA is nearing a deal to buy ad-trading platform Iponweb in what would be its largest-ever acquisition, people with knowledge of the matter said. 

Paris-based Criteo, which has been seeking to diversify its revenue streams, is in advanced talks to purchase Iponweb for about $380 million in cash and stock, the people said. 

The company could announce an agreement as soon as this week, they said, asking not to be identified because the information is private. Shares of Criteo rose 2.1% in pre-market U.S. trading Thursday. 

A representative for Criteo declined to comment, while Iponweb couldn’t immediately be reached.

A deal would help Criteo boost its audience-targeting abilities as major browsers like Apple’s Safari and Google Chrome end support for third-party cookie technology, which was used by Criteo and others to track web users across different sites. Iponweb’s customers include online portal Yahoo!, video-streaming platform Roku Inc., advertising firm Dentsu Group Inc. and TrustX, a marketplace used by content owners such as Walt Disney Co.

Paris-based Criteo has more than doubled in Nasdaq trading this year, giving the company a market value of $2.56 billion. The firm raised its full-year revenue and profit-margin outlook in November, citing “sustained momentum” in the company’s transformation.

Iponweb’s infrastructure helps connect different ad-buying systems and allows campaigns to be directed across multiple platforms. The deal will give Criteo direct access to more publishers as well as boost the range of its offerings to marketing agencies. 

Criteo monitors people’s behavior while using web browsers or apps to determine which advertisements will appeal to them, charging advertisers when someone clicks on the ads. That business has become tougher over the past year, as a push toward greater data privacy has crimped Criteo’s ability to identify individual users. 

Chief Executive Officer Megan Clarken said last month that Criteo’s mergers and acquisitions pipeline was “always hot.” The company has an appetite to do deals, but industry valuations are “incredibly expensive” and the company will make sure it pays the right price, Clarken said at an industry conference. 

Iponweb was founded in the U.K. in 2001 by the husband-and-wife team of Boris and Natalia Mouzykantskii. It now has more than 400 employees spread across offices in North America, Europe and Asia, with engineering centers located in Moscow and Berlin, according to its website. 

(Updates with pre-market trading in third paragraph)

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