Updated at 12:20 p.m. ET: The hearing has ended, and the market appears to be applauding J.P. Morgan CEO Jamie Dimon's performance before a Senate committee Wednesday morning.

Shares of J.P. Morgan were lately up 2.2 percent at $34.50 and the third strongest gainer in the S&P 500 index.

Earlier, responding to a question from Sen. Michael Bennet, D-Colo., Dimon took a page out of Fed Chairman Ben Bernanke’s book and talked about the “fiscal cliff” looming in the new year, when tax cuts and automatic spending cuts will hit simultaneously.

Bernanke has warned that the recovery could suffer because of it and has urged Congress to take steps.

Dimon said, “The fiscal cliff may not wait until Dec. 31.”

He said Congress better do something now before markets and businesses themselves take steps.

He touted the Simpson-Bowles deficit reduction plan and said the specifics are not as important as getting something done.

Sen. David Vitter, R-La., just asked if Dimon thought there could be a “true version” of the Volcker rule, which is named for former Fed Chairman Paul Volcker and is intended to reduce risky trading by banks with customer deposits.

Dimon said: “I think we’re going to really struggle to get it right.”

Vitter asked: What if we were to start with a blank page and rewrote it?

“I think it’s unnecessary,” Dimon said. “It’s just too confusing.” He said risk could be controlled with proper capital and risk controls.

A testy moment when Sen. Alan Merkley, D-Ore., asks Dimon about TARP (the Troubled Asset Relief Program), which was used by the U.S. government to purchase assets and equity from financial institutions to strengthen them during the 2008 financial crisis.

Dimon angrily said his bank did not need TARP, but was asked to accept it by “the Treasury Secretary of the United States.”

Merkley tried to stop him from elaborating, saying: “Sir this is not your hearing.”