The deal could make sense for both Oracle and SAP since it would make both companies more competitive with Workday , analyst Daniel Ives from FBR Capital said in a note.
Ives sees SAP as the likely buyer because Oracle recently spent about $5.3 billion to acquire MICROS Systems.
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SAP Chief Executive Officer Bill McDermott and his former co-CEO, Jim Hagemann Snabe, have spent more than $15 billion since 2010 buying suppliers of Web-delivered applications in areas including human resources and purchasing, as well as database maker Sybase, the report said.
Shares of Concur, known for its travel organizer service "TripIt," jumped 13 percent to $114 in after-market trade. (Click here for the latest quote.)
The stock closed at $100.95 on the Nasdaq on Tuesday, valuing the company at $5.7 billion.