Teruko Noda, a commissioner of the Securities and Exchange Surveillance Commission, has a cabinet full of letters, mostly telling the same story: brokers who allegedly lied and individual investors who lost their life savings.

In all but a few cases, the brokers went unpunished and are still doing business.

"Many times, the evildoers just walk away," Noda said. "We act very slowly, months after the damage has been done. We're understaffed and have limited power."