At one point during his interview, William Coen can’t bring himself to use the word “excessive” when describing a super-abundance of capital. At another, he takes issue with the idea that banks “hold” capital, and the inference that it is a burden they have to bear.

These feel like reflexes born of a 12-year stint as the secretary-general or deputy at the Basel Committee on Banking Supervision – a period during which the committee was engaged in an often bitter running battle with the banking