The president and chief executive of Better Markets, a non-profit group set up by a hedge fund manager to represent the public in the debate over financial reform, has said it is time for Wall Street banks and their chief executives to accept the Volcker Rule.

Jamie Dimon, chairman and chief executive of JP Morgan, is due to appear before the Senate Banking Committee on June 13 as it investigates the $2bn of trading losses in the bank's Chief Investment Office and its impact on the Dodd-Frank financial reform act.