DUBAI - Dubai-based Mashreqbank has hired Citi and Bank of America Merrill Lynch (BAML) as joint bookrunners for a "tap" of a $500 million bond the bank issued in February, sources close to the matter said.

Under a bond tap, an existing transaction is reopened for subscription, using the same documentation as before.

The new paper is being marketed with an initial price guidance of 4% to 4.1%, the sources said.

(Reporting by Davide Barbuscia; editing by Jason Neely) ((Davide.Barbuscia@thomsonreuters.com; +971522604297; Reuters Messaging: davide.barbuscia.reuters.com@reuters.net))