Sprint declined to disclose terms of the deal.
Advertising and other services are becoming a bigger focus for wireless companies, particularly as companies figure out how to address the mobile boom. Sprint's Pinsight Media+ has worked to create an advertising ecosystem for advertisers, and Sprint recently unveiled a mobile content, advertising, and retail partnership with Time Inc. In February, Sprint said it joined with Telefonica to discuss collaborating on creating one of the largest mobile advertising alliances in the world.
"As a long-time partner of Sprint, we've worked together on some of the mobile industry's most successful initiatives," Handmark's Grasis said in a press release. "Joining forces is a natural progression to our relationship and will help scale our mobile media business."
Update, 11:10 a.m. PT: Added comment from Sprint spokesman.