Treasury Secretary Jack Lew declared victory in ridding the financial system of banks that are too big to fail Thursday morning, following up on a promise he made earlier in the year to ensure that no banks remained in a position to receive taxpayer bailouts if they collapse.

In a speech at the Pew Charitable Trusts extolling the Obama administration's regulatory efforts and sketching out future agenda items, Lew said that the 2010 Dodd-Frank financial reform law "ended too-big-to-fail as a matter of law."

Lew had said in July that "if we get to the end of this year and we cannot, with an honest, straight face, say that we have ended too-big-to-fail, we are going to have to look at other options."

On Thursday morning, with the end of the year fast approaching, Lew indicated that he thinks that promise has been met. "Based on the totality of reforms we are putting in place," he said, "I believe we will meet that test."

He immediately hedged his statement, however, saying "to be clear, there is no precise point at which you can prove with certainty that we have done enough. If, in the future, we need to take further action, we will not hesitate."

Lew cited the efforts of regulators to finish writing Dodd-Frank rules in justifying his claim, and in particular referred to several agencies' plans to finalize early next week the "Volcker Rule," a major provision of the law that would limit banks' ability to engage in speculative trading with deposits. Otherwise, however, it was not clear which developments between July and December Lew thought had ended too-big-to-fail.

Lew's assessment runs counter to that of other top regulators who have said in recent months that the largest Wall Street firms are still in a position to receive bailouts if they collapse, and that accordingly they receive an implicit subsidy in raising funds because of that perception.

Janet Yellen, the current Federal Reserve vice chairwoman who is up for confirmation to become head of the central bank in February, said during a confirmation hearing in November that she does believe banks receive a too-big-to-fail subsidy, and that the largest institutions would pose a risk to the entire financial system if they failed.

Furthermore, Sen. Elizabeth Warren, D-Mass., a top Democratic critic of too-big-to-fail banks, has ramped up her campaign to limit banks' size and activities in recent months. In a speech in early November, she argued that the too-big-to-fail phenomenon is worse now than it was before the financial crisis, citing the increased consolidation of financial assets among the top five banks. Warren also said that Congress shouldn't wait for Lew and other regulators to finish writing Dodd-Frank rules, many of which are overdue, but instead should begin working on new legislation enacting more stringent restrictions on big banks.