ASIC commissioner Jeffrey Lucy AM has quit the job after just eight months.
He will take up a part-time position as chairman of the Federal Government's Financial Reporting Council after he officially resigns on December 10 2007.
ASIC's former chairman was meant to serve two years as a commissioner after his three-year tenure in the top job expired in April.
The Treasurer Peter Costello announced on Friday that Mallesons Stephen Jaques lawyer Belinda Gibson will succeed Lucy.
Gibson has been appointed for a three-year term starting on November 5 2007.
Gibson is currently a partner at Mallesons' Sydney office and specialises in transactional advice and corporate and securities law.
Former Australian Securities Exchange chief and the regulator's former head commissioner Tony D'Aloisio succeeded Lucy as chairman in May.
Lucy subsequently took on D'Aloisio's job and has been based in Adelaide.
An ASIC spokesman said he could not comment on Lucy's resignation, which he said was a matter for Treasury.
The Treasurer's office was not available for comment.
Lucy was the FRC's full-time chairman from 2001 to 2003. It is the oversight body for accounting and auditing standard setting arrangements in Australia.
He replaces outgoing chairman Charles Macek
Costello said he will consider hiring another full time ASIC commissioner in the near future.
