US lawmakers meeting in the wee hours on Friday reached a compromise on a bill that will redefine US financial markets and firms for decades, all but guaranteeing the White House its second major domestic policy victory this year.

Months of gruelling negotiations between House and Senate lawmakers, the White House, banks, brokerage firms and consumer groups came to an end in front of a standing-room only Senate hearing room. A 20-plus hour final negotiating session involving the House and Senate, the White House, Treasury, and regulators ended with 27 members of the "conference committee"- all Democrats - agreeing to the measure.