The worlds biggest banks do not need to be broken up, but they do need stricter governance and oversight to prevent tax evasion and money laundering, said Stephen Platt, author of 'Criminal Capital'. Platt added that fining international institutions with limitless resources achieves nothing. In his view, a better solution is to hold senior officers to greater account and put the perpetrators in prison. He said tax evasion was not a focus for regulators prior to the financial crisis but that has changed. Furthermore, Platt said JPMorgan Chase is not too big for CEO Jamie Dimon to manage despite its problems in London. Gregg Greenberg reports from TheStreet's studio.