WASHINGTON  An overhaul of the nation’s financial regulatory system, reached after an all-night Congressional horse-trading session, will vastly expand the authority of the federal government over Wall Street in a bid to curb the free-wheeling culture that led to the near collapse of the world economy in 2008.

The deal between House and Senate negotiators, sealed just before sunrise on Friday, imposes new rules on some of the riskiest business practices and exotic investment instruments. It also levies hefty fees on the financial services industry, essentially forcing big banks and hedge funds to pay the projected $20 billion, five-year cost of the new oversight that they will face. And it empowers regulators to liquidate failing financial companies, fundamentally altering the balance between government and industry.

But after weeks of intense lobbying and months of debate, Congress in the end stopped short of prohibiting some of the practices that led to the crisis two years ago, betting instead that a newly empowered regulatory regime can rein in the big financial players without shackling the markets and drying up the flow of credit to businesses.

“We are poised to pass the toughest financial reform since the ones we created in the aftermath of the Great Depression,” President Obama said on the South Lawn of the White House, before leaving for the Group of 20 meeting in Toronto, where he was expected to press other nations to tighten their financial rules.