Commonwealth Bank's chief financial officer Rob Jesudason has resigned after less than a year on the job, leaving the restive institution with yet another major vacancy to fill. 

Mr. Jesudason is exiting the bank with immediate effect and returning to Hong Kong, where he was previously CBA's international financial services group executive.  He's joining Blockchain software publisher later this year as group president and chief operating officer.

This comes as Commonwealth Bank and other financial institution come under intense scrutiny by the royal commission on banking, and CBA itself is alleged to have repeatedly breached terror financing laws. 

CBA appointed Alan Docherty as acting CFO, but Jesudason's departure adds to the vacancies that new CBA chief executive Matt Comyn must fill.  Two months ago the bank announced that Institutional boss Kelly Bayer Rosmarin, technology chief David Whiteing, and human resources executive Melanie Laing were leaving.  CBA also needs a new head of the retail banking division and a leader to run its wealth operations.