In the wake of WPP's snapping up AKQA for $540 million, Ad Age has learned that Amsterdam-based LBi is reaching out to potential buyers, according to two executives familiar with the process.

The WPP-AKQA deal, announced during the Cannes ad festival, took away one of the industry's largest and best-known digital players not already owned or backed by a holding company. The global-digital breed of agency is hot right now, but for potential acquirers, the list is getting shorter and the agencies on it, smaller.

LBi has less brand cachet than AKQA but is actually bigger, with nearly twice as many employees. Its revenue was just under $250 million in 2011 with $22 million in net profit, according to its annual report. (AKQA has 1,160 people and $189 million in 2011 revenue, according to WPP.) LBi CEO Luke Taylor did not respond to requests for comment.

The shop, publicly traded on the Dutch market, has struggled to gain ground in the U.S., though its annual revenue there grew 16% in 2011 to $53.5 million, according to Ad Age DataCenter. It has a more established reputation in Europe, a factor that 's less of a draw today as the market's growth stagnates. The LBi network has 16 offices in the U.S., Brazil, Western Europe, India, China and Australia, and in November it acquired for about $40 million youth-marketing shop Mr. Youth, which was recently rebranded MRY.

The top 10 digital networks by revenue are all owned by major publicly traded marketing-services companies and there are only a few top-50 agencies ranked by U.S. revenue that are not holding-company-backed. Those include: MediaWhiz, owned by private-equity-backed Hyper Marketing; Acquity Group; Resource Interactive; Gyro; and MePlusYou (formerly known as IMC2).

With the biggest digital-agency deals now largely completed, it's likely that smaller digital agencies could be acquired by smaller ad holding companies or even media or venture capital companies.

"If there is one media or tool that is truly global, it's digital," Maurice Levy, chairman-CEO of the world's third-largest agency company Publicis Groupe, told Ad Age .

Contributing: Rupal Parekh