In a major victory for President Barack Obama, the US Senate has passed the most sweeping overhaul of financial industry rules since the Great Depression of the 1930s.
By a 59-39 margin, lawmakers on Thursday approved an ambitious effort to curb Wall Street excesses blamed for fuelling the 2008 global economic meltdown, amid smouldering voter anger months before November mid-term elections.
"To Wall Street, it says: No longer can you recklessly gamble away other people's money," Democratic Senate Majority Leader Harry Reid. "It says to those who game the system: The game is over."
Senate Banking Committee chair Chris Dodd, a key author of the legislation, said it was "a major step toward creating a sound economic foundation for the American people we represent. This is their victory".
The legislation, Mr Obama's top domestic goal, must still be merged with the House of Representatives' rival version into a compromise measure before the final package can go to the president to sign into law.
House Financial Services Committee chair Barney Frank, a Democrat, told CNBC television that he foresaw smooth sailing and that "the President, I am certain now, will have signed this bill well before the Fourth of July".
The measure aims to rein in big firms' use of high-risk practices blamed for the collapse of 2008, end taxpayer-funded bailout of financial titans previously deemed "too big to fail," and create an unprecedented consumer protection agency to shield Americans from industry abuses.
It also seeks to curb big banks' lucrative, largely unregulated business in complex securities called derivatives, essentially bets on the future cost of an asset, which many businesses use to control risk from volatile prices.
It includes several measures aimed at increasing the transparency at the US Federal Reserve and the central bank's accountability, as well as a measure aimed at blocking International Monetary Fund aid packages like the one for Greece without a guarantee that the money will be repaid.
A few hours before the vote, Mr Obama pledged that the law would not smother the market.
"The reform I sign will not stifle the power of the free market - it will simply bring predictable, responsible, sensible rules into the marketplace," he said in the Rose Garden of the White House.
"Our goal is not to punish the banks, but to protect the larger economy and the American people from the kind of upheavals that we've seen in the past few years," said the President.
Mr Obama also took aim at the financial industry, accusing it of deploying "hordes of lobbyists and millions of dollars in ads" to kill the bill and trying to "water it down."
"Today, I think it's fair to say that these efforts have failed," he said.
Four Republicans joined all but two Democrats to approve the measure, drawing praise from Mr Reid at the end of a month-long, sometimes bitter debate expected to stretch into the House-Senate "conference" to build a compromise.
US Treasury Secretary Tim Geithner said in a statement that he looked forward to working with lawmakers "to produce a sensible, prudent reform bill that strengthens the American financial system and preserves our ability to innovate and compete in a global economy".
The two chambers were to pick negotiating delegates on Monday.
Some of the remaining disputes include curbs on derivative trading and restrictions on investment activities by deposit-holding banks.
Senate Agriculture Committee chair Blanche Lincoln, a Democrat, authored a measure in the bill aimed at ending the largely unregulated derivatives business, a step forcefully opposed by big banks and their lobbyists trying to shape the legislation.
Mr Dodd introduced and then pulled back from but did not withdraw a measure gutting Lincoln's proposal.
Democratic Senators Jeff Merkley and Carl Levin, authors of a measure to enact the so-called "Volcker rule" curbing deposit-holding banks' investment activities, expressed faint hopes the final bill would include it.
The measure, named for former US Federal Reserve chairman Paul Volcker, would stop banks from holding customers' deposits at the same time as making investments for their own gain - so-called proprietary trading.
Curbs on "prop trading" went into effect after the Great Depression. In 1933, the Glass-Steagall Act prohibited commercial banks from underwriting corporate securities, or acting as brokerages, but it was undone in 1999.