Network security systems provider SonicWall, Inc. has agreed to be acquired by an investor group led by private equity firm Thoma Bravo LLC in a deal worth around $717 million.

SonicWALL, whose Internet security hardware competes with Cisco Systems Inc., said its shareholders will receive $11.50 in cash for each share of common stock they hold, representing a 28% premium over SonicWall’s Wednesday closing price of $8.99.

The Investor group includes the Ontario Teachers’ Pension Plane through its private investor department, Teachers’ Private Capital.

“Our agreement with Thoma Bravo represents an attractive valuation for our shareholders, and we look forward to closing the transaction as quickly as possible,” SonicWall Chief Executive Matthew Medeiros said in a statement.

Robert Sayle, a vice president at Thoma Bravo, said the deal will accelerate SonicWall’s organic growth strategy and allow it to pursue consolidation in the network security market. SonicWall reported revenue of $200.6 million last year, down 8% from 2008.

San Jose-based SonicWall said the deal is subject to regulatory and shareholders’ approval and is expected to close later this year. Centerview Partners LLC was the financial adviser to SonicWALL.