"Liquidity is important, but there is such a thing as too much liquidity," Volcker told CNBC. "[There are] people that want to buy oddball securities, and think they can sell them the next day at the same price or a very close price, and that shouldn't be the real world."
"If they're taking risks, they ought to be prepared for the risk and the market risk is part of that," he added.
As for the critics who believe the Volcker rule may be a reason why it is more difficult to trade bonds, "The Volcker rule does not apply, first of all, to government securities, which are the backbone of the liquidity of the bond market," he said.
The Volcker rule prohibits banks from trading for their own accounts.