A group of seven private equity investment firms agreed to buy financial technology company SunGard Data Systems Inc. (SDS) on Monday in a deal worth $10.4 billion plus debt, making it the biggest leveraged buyout in more than 15 years.

The private equity group buying SunGard is led by Silver Lake Partners and includes Bain Capital (search), The Blackstone Group (search), Goldman Sachs Capital Partners, Kohlberg Kravis Roberts & Co. (search), Providence Equity Partners and Texas Pacific Group.

The group is buying SunGard for $36 a share in cash, a 14 percent premium to its closing share price of $31.55 on Thursday on the New York Stock Exchange.

The investor group is also taking on $500 million of SunGard bond debt, which will remain outstanding. Based on Reuters data showing 288.6 million outstanding SunGard shares, the deal would be worth about $10.9 billion including debt.

The investor group said the deal was valued at $11.3 billion, without giving an exact breakdown of how that figure was calculated.

The deal is to be financed by equity contributions from each of the investor firms, plus loans provided by units of banks JPMorgan Chase & Co., Citigroup Inc., Deutsche Bank, Goldman Sachs Group Inc. and Morgan Stanley.

SunGard said its board will recommend the deal to shareholders and will not go ahead with a previous plan to spin off its Availability Services business.

The parties said they expected the transaction to close in the third quarter.

The deal is the biggest leveraged buyout of a public company since Kohlberg Kravis Roberts bought RJR Nabisco for $25 billion in 1989.

SunGard, which earned $454 million on revenues of $3.6 billion last year, works with a majority of Wall Street's financial services companies and supports almost three out of every four Nasdaq trades for its banking, mutual fund and stock exchange clients.

SunGard, based in Wayne, Pa., has also served as an incubator and acquirer of more than 100 technology companies.

Credit Suisse First Boston advised SunGard in the deal, while Morgan Stanley advised the investor group.