The president will speak at an appearance on Thursday at the White House with Treasury Secretary Timothy F. Geithner, an administration official said, speaking on the condition of anonymity because the talks were private. It will come after a meeting with Mr. Volcker.

A similar discussion is percolating in Europe, led by Mervyn King, head of the Bank of England.

The president’s announcement comes as his popularity in public opinion polls is falling because of stubborn unemployment and the stagnant economy, and just days after he suffered a stinging loss when the Republicans won the Senate seat from Massachusetts.

It will be the third time in just a week that he has waded into the battle heating up in Congress over tightening regulation of financial institutions to avoid the sort of abuses that contributed to the near collapse on Wall Street. Last week he proposed a new tax on some 50 of the largest banks to raise enough money to recover the losses from the financial bailout, which ultimately could cost up to $117 billion, the Treasury estimates.

And this week, he served notice to senior lawmakers that he wants an independent agency to protect consumers as part of any financial overhaul legislation.

Image Paul Volcker Credit... Jin Lee/Bloomberg

Only a handful of large banks would be the targets of the proposal, among them Citigroup, Bank of America, JPMorgan Chase and Wells Fargo. Goldman Sachs, the Wall Street trading house, became a commercial bank during this latest crisis, and it would presumably have to give up that status.