The movement to break up the biggest banks has gained considerably more traction than many of the industry's most vocal defenders expected, the former Chairman and Chief Executive of JPMorgan Chase (JPM) said.

William B. Harrison, Jr. has been one of the big banks' most outspoken defenders in the past year, arguing for the utility of the biggest banks in speeches and opinion columns. His arguments have not silenced the regulators, lawmakers, pundits or even some fellow bankers, however, who continue to advocate dismantling of large, complex financial institutions, including JPMorgan Chase.

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