Greystripe, a division of ValueClick Inc. of Westlake Village, today announced expansion and hiring plans that will include new offices and nine new executive hires.

The moves are meant to strengthen the San Francisco division’s position in the mobile ad business in North America and Europe. Since May, the company has doubled its team and opened four new offices in the U.S. while expanding its presence in Europe.

Greystripe has opened new sales offices in Atlanta, Seattle, Minneapolis and Phoenix. The company also announced nine new executive hires. The new senior account executives come from Millenial Media, AOL, Adfusion and other companies.

"We're excited to grow our team and continue expanding in the coming year," Kurt Hawks, vice president of operations for Greystripe said in a statement. "In 2012, we look forward to using this growth to reach advertisers in every significant U.S. market, continue innovation and push the envelope by creating the best in brand advertising for mobile."