BEIJING, March 26 -- Hellman & Friedman LLC, a San Francisco buyout firm, has agreed to purchase business software maker Kronos Inc for 1.8 billion U.S. dollars in cash, its seventh technology acquisition since 1999.

Investors will get 55 dollars a share, Chelmsford, Massachusetts-based Kronos said in a statement. Kronos had 3,400 employees and sales of 578 million dollars in 2006, according to its Website.

Kronos, whose programs manage payrolls and employee evaluations, made at least six acquisitions last year, including a deal for software maker Unicru Inc. Hellman's oversight will help Kronos reach its goal of doubling sales, according to Chief Executive Officer Aron Ain.

"It's a surprise from the standpoint that Kronos has typically been the acquirer, not the acquired," Matthew L. Weiss, an analyst at Maxim Group LLC in New York, said in an interview. "We expect Kronos to acquire companies going forward. If I was a shareholder I'd be happy with a US$55 takeout price."

Kronos, named after the Greek word for time, got its start in 1977 selling microprocessor-based time clocks, according to its Website. The company went public in 1992. Customers have included furniture retailer Ikea, Time Warner Cable Inc and the Department of Homeland Security, Bloomberg News said.

Hellman & Friedman will add Kronos to other purchases such as its acquisition of DoubleClick Inc in 2005, and a deal for Intergraph Corp last year, both listed on the firm's Website. The firm has made 21 acquisitions since 1999, according to external spokeswoman Monica Everett.

The transaction should be completed in the fiscal fourth quarter pending shareholder and regulatory approval, according to the statement. The transaction will be financed in debt and cash on hand.