SINGAPORE, Feb 4 (Reuters) - Alibaba Group Holding Ltd on Thursday set initial price guidance on its $5 billion bond offering, according to a term sheet reviewed by Reuters. Alibaba flagged a price range of 130 basis points over U.S. 10-year Treasuries for the 10-year tranche and 140 basis points over U.S. 20-year Treasuries for the 20-year tranche. It is selling the bonds in four tranches, the term sheet showed. The company has opened the book for its U.S. dollar bonds worth up to $5 billion, according to the term sheet. (Reporting by Scott Murdoch; Writing by Anshuman Daga; Editing by Tom Hogue)