In business software, the big fish can't seem to avoid being swallowed by the much bigger fish.

Oracle, which has been on a furious acquisition tear to fend off SAP of Germany and Microsoft, wants to buy another company, BEA Systems, for $17 a share in cash, or $6.7 billion.

The offer, which Oracle announced today, represents a 25 percent premium on BEA's closing price on Thursday. Shares of BEA shot up 32 percent, to $18.11, in trading today.

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

BEA was cool to the proposal saying that the offer "significantly undervalues" the company.

In a reply to Phillips that the company released, BEA said: "It is apparent to our board, however, that BEA is worth substantially more to  Oracle, to others and, importantly, to our shareholders than the price indicated in your letter. As we have indicated to you previously, we believe that the absence of current financial information in the public markets limits investor visibility into our performance. We expect that this will be corrected in the near future when we become current on our S.E.C. filings."

BEA has had to postpone filing financial statements as it completes an internal investigation into the backdating of stock options.

Oracle has grown by spending more than $25 billion on more than 30 acquisitions in the past few years, including deals for Hyperion Solutions, PeopleSoft, and Siebel Systems. Its chief rival, SAP, has taken a page from its playbook, offering last week to acquire French enterprise-software company Business Objects for about $6.8 billion.

A deal would be a coup for activist investor Carl Icahn. He recently raised his stake in BEA to 13.2 percent from 11 percent, and called on BEA management to put the company up for sale.

BEA, based in San Jose, California, makes middleware software, which supports corporate technological processes from billing to securities trading.

As the New York Times' DealBook blog points out, BEA has been seen as takeover target for about half  of its 10 years as a publicly traded company