SizmekPrivate Equity Firm Vector Capital announced Wednesday it has entered into an agreement to acquire Austin-based Sizmek, an advertising technology company, for $3.90 a share, valuing the deal at $122 million.

San Francisco-based Vector Capital, founded in 1997, has invested $1.6 billion in more than 40 technology companies.

“We believe this transaction provides Sizmek with the resources and flexibility to execute upon our long term strategy of becoming the leading independent, global ad management platform,” Neil Nguyen, President and Chief Executive Officer of Sizmek, said in a news statement. “We are excited to partner with Vector and believe this transaction benefits our customers, employees, partners and shareholders.”

Sizmek, founded in 1999 in New York, moved its corporate headquarters to Austin a few years ago. The company works with more than 19,000 advertisers and 3,700 agencies. It serves more than 1.3 trillion ad impressions a year. Sizmek has offices in 65 countries and has about 1,000 employees.

“We are enthusiastic to partner with the management team and the talented group of employees at Sizmek,” Alex Beregovsky, Managing Director at Vector Capital, said in a news statement. “We plan to invest in the Company’s growth, to further strengthen its industry-leading open ad management platform, to launch adjacent product offerings as well as to support Sizmek with capital for acquisitions.”

The buyout price per share is 65 percent more than Sizmek’s 30-day volume weighted average trading priace of $2.36 per share on August 2nd. After the deal is done, Sizmek will become a privately-held company. The companies expect to complete the deal by the fourth quarter of this year pending regulatory and shareholder approval.