When Tim Geithner, US Treasury secretary, wants a first-hand account of how financial markets are interpreting government policies or reacting to the latest crisis, the man he turns to most often is Larry Fink of BlackRock.

Mr Fink, the group’s chief executive, features more frequently in Mr Geithner’s diary in a recent 18 month period than any other corporate executive, according to a Financial Times review. The two men spoke on at least 49 separate occasions, an average of about once every 11 days.

Calls and meetings with Mr Fink in 2011 until the end of June this year outnumber the combined calls and meetings with the heads of the six largest US banks by assets. Mr Geithner’s second most frequent interlocutor in the corporate world was his old boss, former Treasury secretary, Robert Rubin, now at Centerview Partners, who spoke to him 33 times in the same period.