Washington, Marc 14 (IANS): America's central bank has found four of 19 largest US financial firms, including Citi Bank led by Indian American CEO Vikram Pandit, wanting and which need to do more to weather another deep recession.

However, 15 financial firms have enough capital to cover losses under extreme circumstances: an unemployment rate of 13 percent, a 50 percent decline in stock prices and another 21 percent in housing prices, the Federal Reserve said releasing its stress test results Tuesday.

Three banks - Citigroup, Ally Financial, and SunTrust - would likely need new capital from either investors or the government in the Fed's adverse economic scenario. A fourth financial firm, insurer Metlife, would likely be in need of assistance as well.

A senior official at the Fed cited by CNN said all four of the banks would need to submit plans that would detail how they would increase their capital to make them less vulnerable in a downturn.

Citigroup said it remains among the best capitalised large banks in the world. However, it said it would not be able to raise its dividend as it hoped, and would submit a revised capital plan to the Fed.

All told, the Fed said that the nation's 19 largest banks could lose as much as $534 billion. The majority of that would come from soured loans and trading losses from a "global financial market shock."

The Fed said that the majority of banks would be able to absorb the losses because they have increased their collective capital by more than $300 billion since the start of 2009.

The stress test was modelled on an extreme negative scenario and not its actual outlook for the economy, it said.