Adamson is believed to be leaving his role as director of supervision at the FCA after seven years in the role, ahead of a critical report on the regulator which is due next week.
In March, a story in The Telegraph said the FCA was planning an inquiry into 30 million pension and investment policies.
The story, which named Adamson as its source, took the industry by surprise and wiped around £3bn off the market value of the largest insurance firms overnight, including Aviva and L&G.
The FCA later clarified that its review of the policies would be narrower in focus but the matter was described as an "extraordinary blunder" by the chair of the Treasury Select Committee, Andrew Tyrie, and George Osborne said at the time that he was "profoundly concerned" by the matter.
The results of an inquiry into the issue, by Clifford Chance, are expected next week.
Commenting on the news of Adamson’s reported departure, Bobby Moore, senior partner at Buchanan financial PR agency, told PRWeek that issues like this were usually sorted out "behind closed doors".
He said: "These things do happen although, usually, the result is not as drastic as this. It must have been a serious error of judgement. Usually these things are sorted out behind closed doors but it was obviously considered serious enough for him to lose his job."
The FCA declined to comment
The FCA declined to comment
