NEW YORK ( TheStreet) -- America Online ( AOL) was rising Wednesday after the online media company said it plans to acquire Adap.TV to improve its video advertising capabilities, offsetting a growth in sales that missed analyst forecasts. Shares were gaining 2.1% to $36.92, extending AOL's 2013 advance to 25%. The acquisition comes as AOL continues to produce mixed results. Revenue increased $541 million from $531 million in the first quarter but short of analysts' average forecast of $544.6 million. Operating income of $108.3 million beat analyst expectations of $101 million. The Adap.tv deal was the focus of investor interest as the new platform promises to help AOL reap more advertising and distribution revenue for the slate of video programming Tim Armstrong, AOL's chairman and CEO, has been spending millions of dollars creating. "AOL takes a major step forward today with another quarter of growth and our agreement to acquire the Adap.tv video marketplace platform that will make AOL a clear global leader in the most important growth segment in our industry - online video," Armstrong said, in a statement. Adap.tv will cost AOL $405 million, making the transaction the company's largest deal since splitting from Time Warner ( TWX) in 2009. AOL said it would pay $322 million in cash and $83 million in stock for Adap.tv, a San Mateo, Calif.-based company that provides video advertising services for ad agencies, publishers and large brands. The buyer said that Adap.tv's services are used by 83 of the Ad Age 100 largest global advertisers. AOL shares were rising 1.6% to $36.72 in mid-morning trading. Post-deal, AOL, which manages a portfolio of Web properties and services, said it would be able to provide video ads across all screens and offer a unified management platform for advertisers and publishers. Digital video and advertising are two areas of focus at the company. "AOL is a leader in online video and the combination of AOL and Adap.tv will create the leading video platform in the industry," Armstrong said in a statement. "The Adap.tv founders and team are on a mission to make advertising as easy as e-commerce and the two companies together will aggressively pursue that vision."