BMC Software launched a $28 per share cash tender offer to BladeLogic shareholders Friday just four days after the companies' merger plans were announced.

The deal offers a lucrative exit for venture backers including Bessemer Ventures and Battery Ventures, whose entrepreneur-in-residence program nurtured BladeLogic. Battery's 2.9 million shares represent about 10 percent of the company. After a partial cash out in BladeLogic's initial public offering in 2007, Battery stands to reap another payday worth about $80 million.

"We started it in 2001 with an entrepreneur-in-residence and stuck with it during really tough times to be a technology company," Battery general partner Dave Tabors said in an e-mail. "We scaled it, took it public, and now BMC recognizes its strategic position in a huge market."

Battery entrepreneur-in-residence Vijay Manwani became chief technology officer of BladeLogic.

Shares of BMC closed at $33.39, up $.69, or 2.1 percent, on the New York Stock Exchange on Thursday, while BladeLogic finished at $27.81, up $.02, or .07 percent, on the Nasdaq Global Market.

The deal, worth about $831 million, based on 29.7 million shares outstanding of BladeLogic, is designed to bolster BMC as it faces off against Hewlett Packard in the data center automation market.

The tender offer from Houston-based BMC will expire at midnight April 17 unless extended, according to government filings. The deal has been approved by the BladeLogic board of directors.