COVENTRY, England—Reducing bank capital requirements as part of a planned overhaul of postcrisis U.S. financial regulation would be a bad idea, a senior Federal Reserve official said Saturday.

“Significantly reducing capital requirements would reduce the safety of the system and we certainly hope it’s not going to happen,” Fed Vice Chairman Stanley Fischer said while answering questions following a speech to students at the Warwick Economics Summit in Coventry, England.

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