FSA chairman Adair Turner informed staff this morning in an internal email and a public announcement is due to be made today. (Update: a public announcement has now been made.)
A source close to the regulator says Dewar is leaving becasue she does not want to be considered for the chief executive role, to replace Hector Sants, causing her to re-evaluate her priorities.
Dewar has been a managing director at the FSA since January 2008, initially of the wholesale business unit and most recently of the risk business unit.
She joined the London Stock Exchange’s Listing Authority in 1998 and from 2002 to 2005 was the head of the UK Listing Authority in the markets division of the FSA, before becoming director in October 2005.
As managing director of the risk business unit, Dewar has been responsible for sectoral and market-wide risk identification and mitigation, the overall risk management process and specialist prudential and conduct risk support to supervision and policy formation, covering prudential policy, conduct policy and markets policy.
She also had responsibility for supervision of all regulated markets and the related infrastructure, including clearing and settlement and the UK Listing Authority.