AT&T will sell Xandr, its programmatic advertising marketplace, to Microsoft, the telco announced.

Financial terms of the deal were not disclosed; the transaction is subject to customary closing conditions, including regulatory reviews. Xandr has formally been part of WarnerMedia, and the sale of the ad unit to Microsoft comes as WarnerMedia has set a deal to merge with Discovery.

Microsoft’s proposed acquisition of Xandr does not include the advertising sales business supporting DirecTV, which AT&T spun off in a deal with TPG Capital earlier this year. AT&T, which has embarked on a strategy to reduce its massive debt load through asset divestitures, has been looking to offload Xandr for more than a year.

According to Microsoft, Xandr’s technology strategically complements Microsoft’s current advertising offerings and will “help accelerate delivery of digital advertising and retail media solutions for the open web” by combining Microsoft’s audience intelligence, technology and global advertising customer base with Xandr’s data-driven platform.

“Microsoft’s shared vision of empowering a free and open web and championing an open industry alternative via a global advertising marketplace makes it a great fit for Xandr,” Xandr EVP and GM Mike Welch said in a statement. “We look forward to using our innovative platform to help accelerate Microsoft’s digital advertising and retail media capabilities”

Mikhail Parakhin, president of web experiences at Microsoft, commented, “With Xandr’s talent and technology, Microsoft can accelerate the delivery of its digital advertising and retail media solutions, shaping tomorrow’s digital ad marketplace into one that respects consumer privacy preferences, understands publishers’ relationships with consumers and helps advertisers meet their goals.”

AT&T formed Xandr in September 2018, combining its TV and digital advertising businesses, including digital ad marketplace AppNexus, which the telco bought for a reported $1.6 billion that year. Xandr was initially led by CEO Brian Lesser, who exited the post in the spring of 2020 after AT&T decided to combine Xandr with WarnerMedia.

Xandr had ambitions of becoming a dominant player in cross-platform advertising. WarnerMedia had been a founding member of Open AP, an initiative to facilitate advanced TV ad buying across multiple media companies, alongside ViacomCBS and Fox Corp. The Open AP consortium later added NBCUniversal and Univision to its ranks. After AT&T’s creation of Xandr, WarnerMedia exited Open AP in 2019 — but this June, the two rivals reached a truce and with a new data-collaboration agreement.

Microsoft has worked with Xandr (and its predecessor businesses) for 10 years. In 2020, Xandr joined the Microsoft Audience Network, which serves “Microsoft Audience Ads,” a native advertising solution built by the Bing search platform.