In Europe earlier today, traders felt strongly enough about a rumor regarding a Microsoft/SAP acquisition that they drove up SAP's stock by nearly 2%.By 8:30 a.m. East Coast time in the United States, SAP shares were up 1.8% to 35.6 euros as "traders cited market talk of bid interest from Microsoft," according to a story posted at 8:47 a.m. by Reuters. The stock closed today at 35.4 euros, up 1.32%. I've put in a request for comment to SAP's PR staff, but no word yet.

It's unclear where the rumor came from, but there could be something to it. Remember, Microsoft looked at acquiring SAP just about three years ago. In June 2004, as the Department of Justice's antitrust suit against Oracle regarding the PeopleSoft acquisition was beginning to unfold, Microsoft decided to be up front about the talks it had with SAP before the details came out in court. Microsoft confirmed talks had gone on for months and issued a statement saying the acquisition didn't occur "due to the complexity of the potential transaction and subsequent integration."

Such a deal would still be complex, of course. It would likely get scrutiny from regulators in Europe (with whom Microsoft has had problems in the past) and the DOJ. And with a market cap of about $65 billion (44.1 billion euros), could Microsoft even digest a big fish like SAP? Aside from the phenomenal cost, integration would be formidable.

But as a combo, both companies could certainly use each other. As Microsoft rises as an enterprise player in both servers and databases, and SAP continues to reign in enterprise apps, the two could walk into CIO and CFO offices with a one-two combo that would cause serious problems for IBM and Oracle.

Given the software industry's rapid consolidation, though, an SAP acquisition would be far from shocking. There are other theories out there. Jason Maynard, a software analyst with Credit Suisse Worldwide, recently told InformationWeek Editor in Chief Rob Preston that he thinks the "No. 1 sea change deal" in the software industry over the next two to four years will be IBM acquiring SAP. IBM's Global Services and vertical industry expertise would introduce SAP into many more accounts, Maynard reasons, and SAP would be freed from focusing on its NetWeaver middleware layer to concentrate on what it does best: core business apps.

Could be both IBM and Microsoft are talking to SAP. But either way, there's been enough chatter about SAP as an acquisition target in recent months for me to suspect that SAP is talking and listening to potential acquirers.