Bain Capital Partners LLC on Thursday announced it has agreed to buy a stake in outsourcing company Genpact Ltd from General Atlantic LLC and Oak Hill Capital Partners LP for $1 billion.

Bain, a private equity firm, is buying about 30% of Genpact’s stock outstanding for $14.76 a share, according to a statement. The transaction is expected to close this year after a special dividend of $2.24 a share to all shareholders, including General Atlantic and Oak Hill.

“Bain Capital has a long-term perspective, which is critical to building value, particularly in a company like ours,” chief executive officer N.V. Tiger Tyagarajan said in the note. “We look forward to working with Bain Capital as we continue to make enterprises around the world run better by continuously improving their business processes.”

Genpact began operations in 1997 as an India-based computer-services unit of General Electric Co. that assisted the US firm’s finance division.

The Bermuda-based company still gets a quarter of revenue from GE, Tyagarajan said last month.

Oak Hill and General Atlantic acquired 60% of the company, formerly known as GE Capital International Services, for $500 million in 2004.

When the deal closes, Bain will name four people to Genpact’s board, replacing the Oak Hill and General Atlantic directors. The selling shareholders will still own about 10% of Genpact’s shares outstanding after the transaction. Bain, a Boston-based firm that manages almost $65 billion, has agreed not to sell any Genpact shares for two-and-a-half years, according to the note.

Tyagarajan will remain CEO, and Robert Scott, a former Morgan Stanley executive, will stay on as chairman.

Genpact on Thursday also reported June quarter net income increased 56.6% to $61.1 million compared with the same period last year, largely due to a foreign exchange gain of $21.97 million during the quarter compared with the $1.13 million in the corresponding quarter last year.

Genpact’s revenues were up 17.6% to $467.6 million, from $397.6 million in the second quarter of 2011.

Revenues rose 7.4% sequentially.

Tyagarajan said the company’s revenue growth was broad-based across geographies, including Europe, and all major service lines, including finance and accounting. “We have delivered a terrific first half of the year, despite some softness around discretionary spending.”

He added that the company continues to expect full-year revenue to be in a range of $1.86–1.90 billion, and adjusted operating income margin in a range of 16–16.5%.

Genpact, which handles technology services and other business tasks, operates from 18 countries. The company has more than 3,000 employees in the US, representing about 5% of its total as of the end of 2011.

Genpact, which held its initial public offering in 2007, declined 1.6% to $17.15 at the close in New York. The stock has advanced 15% this year. Bloomberg

Mint’s Surabhi Agarwal in New Delhi contributed to this story.