Software company Oracle Corp. said Monday that it is buying RightNow Technologies Inc. for about $1.5 billion so it can offer a broader range of software and services that help businesses manage customer service.

Oracle is offering $43 per share for the tech service company from Bozeman, Mont.. That is a 19.6 percent premium over RightNow's closing price of $35.96 on Friday.

On Monday, RightNow's stock rose $6.85, or 10 percent, to $42.80 in premarket trading.

RightNow's board has agreed to the deal which is subject to shareholder approval. Oracle expects to complete the deal by late this year or early next.

RightNow's main product helps companies manage customers' questions and complaints. It is delivered over the Internet — or "cloud" — rather than by installing software directly on computers. The deal follows a smaller acquisition Oracle made in the space when it bought InQuira to expand its selection of products that help companies keep their customers happy. Terms of that deal, announced in July, were not disclosed.

Shares of Oracle, which is based in Shores, Calif., slipped 12 cents to $32 in premarket trading.