Private equity firm Hellman & Friedman agreed to buy advertising technology and data company DoubleClick for $1.1 billion, DoubleClick announced Monday.

"This transaction provides great value to our stockholders and underscores the strength of our industry leading position and DoubleClick’s business model," DoubleClick chief executive Kevin Ryan said in a statement.

Under the terms, Mr. Ryan will step down as the company’s CEO and the new chief executive will be announced later.

DoubleClick’s shareholders will receive a 10.6% premium over the average closing price of DoubleClick’s shares for the past month. Under the deal, DoubleClick stockholders will receive $8.50 in cash for each share of DoubleClick stock, the company said in a statement.

DoubleClick reported a first-quarter loss of $917,000, or 1 cent a share, compared to a profit of $7.7 million, or 5 cents a share, in the same period of 2004.

The deal is expected to be completed in the third quarter, DoubleClick said.