WAN optimisation and web security vendor Blue Coat is set to be acquired by a group led by Thoma Bravo, a private equity firm, for $1.3 billion (£830 million).

The Blue Coat board has accepted the offer and recommended it to shareholders.

The Thoma Bravo group also includes investment company the Ontario Teachers' Pension Plan, which is currently suing IT services firm CSC over allegations of misreported prospects on the NHS National Programme for IT.

Under the terms of the agreement, Blue Coat shareholders will receive $25.81 in cash for each share of Blue Coat common stock they hold, representing a premium of approximately 48 percent over Blue Coat's closing price on 8 December.

David Hanna, chairman at Blue Coat, said: "Over the last six months, our Board of Directors engaged in a comprehensive review of all strategic options available to Blue Coat.

"After an extensive evaluation of strategic alternatives with our independent advisors, the Board has determined that the definitive agreement with Thoma Bravo provides an attractive all-cash valuation to our shareholders."

Orlando Bravo, managing partner at Thoma Bravo, added: "As a private company, Blue Coat will be better positioned to innovate at an accelerated rate and achieve a higher level of growth."

The transaction is subject regulatory approvals as well as the approval of Blue Coat shareholders. Blue Coat expects the transaction to close in the first calendar quarter of 2012.