Malaysian central bank Governor Zeti Akhtar Aziz prepares to leave in April after three decades at the central bank. Whoever is chosen as her successor will have very big shoes to fill, said Wellian Wiranto, an economist at Oversea- Chinese Banking Corp. in Singapore. This is especially so since the global environment remains uncertain and Malaysia is deemed relatively vulnerable to swings in global investor sentiment -- in part due to domestic political rumblings. Zeti served as a deputy governor before she took the top job in 2000. The central bank declined to comment on whether any of the three current deputies are in the running this time.