Treasury Secretary Timothy Geithner said plans to retool the regulatory structure of the financial system are moving forward, while he vowed the Barack Obama administration will prevent the industry from returning to excessive risk taking and other old habits. "I don't think the financial system is reverting to past practice, and we won't let that happen," Geithner said. "The big banks are running with much less leverage now, much more conservative liquidity cushions. There's been a significant shrinking of their balance sheets, getting rid of bad assets and cleaning up. And the weakest parts of the system don't exist anymore."