HONG KONG (Reuters) - Saudi Aramco launched its first US.dollar-denominated sukuk bond on Wednesday which will be issued in three tranches, according to a term sheet seen by Reuters. The deal will consist of three, five and ten year tranches, the term sheet showed. Potential investors have been given pricing guidance for the three year of U.S. Treasuries plus 105 basis points, for the five year of U.S. Treasuries plus 125 basis points and for the ten year of U.S. Treasuries plus 160 basis points. Aramco chose to issue Islamic bonds over conventional ones due to high demand for the instrument as a result of few dollar sukuk sales from the Gulf this year, a source told Reuters on Monday. The final terms and size of the transaction are expected to be set on Wednesday. Aramco has been widely expected to become a regular bond issuer after its debut $12 billion bond deal in 2019 was followed by an $8 billion, five-part transaction in November last year, also used to fund its dividend. There are 29 active and passive bookrunners on the deal, the term sheet showed. Reporting by Scott Murdoch in Hong Kong; Editing by Edwina Gibbs Our Standards: The Thomson Reuters Trust Principles.