Her exit has been revealed in a statement released this morning by the FCA, but it does not say what she plans to do next.
On 7 January 2016 she announced that she decided in early December 2015 to withdraw from the process to appoint the permanent chief executive of the FCA but would continue as interim chief executive until a permanent replacement was in post.
Andrew Bailey was appointed as the new chief executive on the 26 January and is due to take up the position on 1 July.
Ms McDermott became the acting chief executive in September 2015. She has previously been Director of Supervision and Authorisations and prior to that Director of Enforcement and Financial Crime. Ms McDermott joined the FCA's predecessor the Financial Services Authority in 2001.
John Griffith Jones, Chairman of the FCA, said: “Tracey has done a terrific job leading the FCA over the last seven months, building on the enormous contribution she has made in her various roles over the previous fifteen years.
"Transitions are always challenging and her energy and clarity of purpose have been invaluable in steering the organisation in the right direction. I know she will continue to lead the FCA with the same commitment until Andrew Bailey arrives in July and I and the Board are grateful for her unstinting support.”