DUBAI, March 29 (Reuters) - Saudi Aramco is marketing its riyal-denominated sukuk at 25 basis points over the Saudi Arabian Interbank Offered Rate (SAIBOR), sources familiar with the matter said on Wednesday.

The Islamic bond, part of a 37.5 billion riyal ($10 billion) sukuk programme, has a seven-year maturity and is expected to be issued next Monday, said one of the sources.

The bond size could go as high as 6 billion riyals, sources told Reuters in February.

(Reporting by Davide Barbuscia; Editing by Andrew Torchia) ((Davide.Barbuscia@thomsonreuters.com;))