In a House hearing, Ben S. Bernanke, the Federal Reserve chairman waged a fresh battle against efforts to scale back the Fed’s role in overseeing banks.

Regional bank Comerica Inc on Wednesday said it has repaid $2.25 billion of federal bailout money, while Hartford Financial Services Group Inc said it sold $1.95 billion of stock to help repay $3.4 billion of its bailout funds.

Ben Bernanke, chairman of the Federal Reserve, appealed to Congress to preserve the central bank s supervision of the financial system as lawmakers consider removing some of the Fed s powers.

The government s $700 billion economic bailout will actually cost the government a fraction of that total, CBO reports.

Top central bankers present and past on Wednesday joined forces against a plan to strip the Fed of its oversight of smaller banks, saying the knowledge it gains from that role is vital to monetary policy.

* Fed should supervise small banks, Bernanke says * Insights culled from bank oversight aid monetary policy

The U.S. central bank s commitment to an extended period of low interest rates is not yet in need of change, Federal Reserve Bank of Dallas President Richard Fisher said on Wednesday.

The quadruple witching expiration of futures and options should give stocks a lift into Friday, traders say. Major headlines for the market Thursday are weekly jobless claims data and CPI, both at 8:30am.

Market gains depend on the liquidity supplied by the Fed. When the tap is turned off, the tide may turn. This edition of Dave s Daily also looks at ETFs for semiconductors, financials and other sectors.

Global equity markets and commodity prices rallied on Wednesday after the Federal Reserve s signal on Tuesday that US interest rates would remain close to zero for longer and the Bank of Japan on Wednesday said it would take further steps to boost credit growth.