AT&T just signed deals to sell ads for Bloomberg and Walmart-owned Vudu, and it's the latest sign of the telecom's big ambition to pitch external publishers

Greg Sandoval/Business Insider

AT&T CEO Randall Stephenson.

• AT&T's ad division, Xandr, has added Bloomberg and Vudu to its video marketplace that lets advertisers buy ads across multiple publishers.
• The 4-month old marketplace is one way Xandr is positioning itself to not be a so-called walled garden for advertisers.
• A+E Networks, Vice and Hearst Magazines are also part of the marketplace in addition to AT&T's brands.
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AT&T's advertising unit Xandr wants to cozy up to big publishers.

On Tuesday, the company announced that it has added Bloomberg and Walmart-owned streaming service Vudu to its video ad marketplace called Community.

Xandr pitches Community to advertisers and publishers as a way to buy and sell video ads across multiple publishers, including AT&T's brands like CNN and Warner Bros. Since launching in May, Xandr has signed deals that allow AT&T to sell some advertising from external publishers like Hearst Magazines, Cheddar, A+ E Networks, and Vice. Xandr also sells advertising space on streaming video apps Tubi, Xumo, and Philo.

Advertisers use Community to balance their investments between TV and digital. For example, AT&T's trove of data can identify "light TV viewers." Advertisers say they've used Xandr to find TV-like audiences online to hit their reach and frequency goals.

Read more: Some marketers say AT&T's big plan to reinvent advertising is taking shape but worry that it will shut out competitors

"We are helping advertisers reach interested consumers on whatever device they watch their favorite show," said Brian Lesser, CEO of Xandr in a statement.

Xandr announced its deals with Bloomberg and Vudu at its Relevance Conference in Santa Barbara, Calif.

Marketers are skeptical that AT&T can work across the industry

Some marketers say it's unclear how much data and proprietary technology the telecom giant will share, however.

AT&T is also competing with similar technology that networks are developing, such as Open A.P., a joint venture with NBCUniversal, Fox Corp. and Viacom. AT&T's WarnerMedia was also involved in Open A.P. before pulling its involvement in April.