Oracle Corp on Friday said it offered to buy BEA Systems Inc for about $6.66 billion, its latest effort to up the ante against Microsoft Corp. and Germany's SAP in the fiercely competitive market for business software.

Oracle offered $17 per share in cash for BEA, which is a 25 percent premium over BEA's closing stock price on Thursday. Shares jumped in premarket trading to match the offer price.

This proposal is the culmination of repeated conversations with BEA's management over the last several years, said Oracle President Charles Phillips. We look forward to completing a friendly transaction as soon as possible.

Billionaire investor Carl Icahn has been pushing BEA to put itself up for sale, and by Oct 4 had built a 13.22 percent stake in the company.

BEA sells application server software and so-called middleware, which is used by software developers to establish systems on which other software applications operate. Its products are used in transaction processing, billing, customer service, provisioning, and securities trading.

Oracle has spent the last several years buying up other specialty software makers, in an effort to compete with Microsoft and SAP.

The proposed deal is Oracle's biggest since it bought Siebel Systems for about $6 billion in early 2006. Earlier this year it bought Hyperion Solutions for more than $3 billion.

(Reporting by Christopher Kaufman and Bill Berkrot)