With M&A fever in the air, Siebel Systems ( SEBL) bounced nearly 10% Wednesday, apparently on a trading-floor rumor that IBM was considering a buyout. Several analysts quickly discounted the notion, saying that IBM has strong partnerships with SAP ( SAP) and PeopleSoft ( PSFT) that would be threatened by a major move into the customer relationship management market. Heather Bellini of UBS Warburg said the rumored move would be out of step with IBM's software strategy. "IBM's application strategy has historically been much more of a partnership strategy versus an acquisition strategy. Rather, the company has focused its software acquisitions on infrastructure software technology, which is evident by its acquisitions of Rational early this year and Crossworld in late 2001," she wrote in a note to clients. Warburg has a banking relationship with IBM but not with Siebel. Earlier this week, PeopleSoft itself announced its intention to buy rival software maker J.D. Edwards for $1.7 billion in stock, and insiders are expecting more consolidation in the enterprise software market. Bellini noted that "Siebel is more likely to be the acquirer versus the acquiree, which means buying the stock as a potential takeover target could prove to be disappointing." In any case, enterprise software stocks are still gaining value. Oracle, for example, closed Wednesday at $13.58, its highest level since March of 2002, and the Goldman Sachs software index has gained 11% this year. Siebel finished the day up 95 cents, or 9.9%, to $10.55 on volume that was about double that of an average trading day, while IBM was up 43 cents, or less than 1%, to $84.25.