IGate Corp. struck a deal to acquire a majority stake in Patni Computer Systems Ltd., an IT services firm based in Mumbai, India, in a transaction valued at up to $1.22 billion.

The deal calls for iGate to acquire a 45.6 percent stake in the Patni from its founders as well as a 17.4 percent stake now owned by private equity firm General Atlantic. In addition, iGate will make an offer to Patni's public shareholders to acquire an additional 20.6 percent stake in the firm.

IGate will finance the purchase with a combination of cash, debt and equity financing. Viscaria Ltd., a company backed by funds advised by Apax Partners, will buy $270 million in iGate preferred stock to help fund the Patni deal. The preferred stock is convertible to common stock with a conversion price of $20.30. Viscaria could increase its preferred stock investment by an additional $210 million.

IGate also has a commitment for debt financing of up to $700 million from Jefferies & Company Inc.

Patni posted revenue of $689 million in the 12 months ended Sept. 30, 2010. It has 16,556 employees, 282 customers, 22 global delivery centers and offices in 30 locations worldwide.

IGate reported revenue of $252 million in the 12 months ended Sept. 30, 2010, It has 8,278 employees, 82 customers, seven global delivery centers and offices in 16 countries.