Fiserv Inc. (FISV), which sells data-processing technology and services to the financial industry, said Thursday it would buy CheckFree Corp. (CKFR), an online check and bill-paying company, for $4.4 billion.

CheckFree shareholders will receive $48 per share, a 30 percent premium to the shares' Aug. 1 closing price of $36.83.

The deal, one of a string of recent transactions in the financial processing sector, should help Fiserv boost its revenues and reach a broader array of customers. Fiserv expects $100 million in annual cost savings and more than $125 million in extra revenue for the combined company.

The deal is expected to add to Fiserv's underlying cash earnings per share in 2008.

Data and transaction processing businesses often need to make heavy investments in technology to eke out cost savings and processing efficiencies. Those investments can be difficult for smaller companies to finance on their own, which has helped spur mergers in the sector.

Fiserv is being advised by Credit Suisse, while CheckFree is advised by Goldman Sachs. Fiserv's legal adviser was Sullivan & Cromwell, while CheckFree's was Wachtell, Lipton, Rosen & Katz.

The deal is expected to close by year-end.