Financial regulators have backed reforms aimed at improving the way the New York Stock Exchange (NYSE) is run.
Members of the Securities and Exchange Commission (SEC) voted unanimously in favour of the overhaul, which would make NYSE directors more independent.
However, the SEC said it may propose more far-reaching changes when it reviews the structure of the US financial markets next year.
The reforms follow a row over 'fat cat' pay at the NYSE this summer.
The dispute began in August when it emerged that former NYSE chairman Dick Grasso was entitled to a string of benefits and incentive payments worth a total of $140m (£80m).
The scale of the package angered investors, who said it cast doubt over standards of governance at the exchange.
Under the reforms, drawn up by NYSE interim chairman John Reed, the exchange would be run by a board of directors with between six and 12 independent members, and a separate 20-member board of executives.
The exchange's activities would also be overseen by a "chief regulatory officer" who would report to a committee of directors.
But the shake-up has already been criticised as inadequate by major investors and US legislators, who argue that it does not do enough to curb the influence of the NYSE's member firms over how the exchange is run.
Under Mr Reed's proposals, NYSE members would retain the power to elect some of its directors.
Separately, the NYSE said it had also agreed to separate the roles of chairman and chief executive.
SEC chairman William Donaldson - a former head of the NYSE - welcomed the move.
"In this way, the NYSE should be in a better position to protect against the concentration of too much executive authority in one individual," he said.
The SEC's green light for the new NYSE regime came a day after the US's biggest pension fund, Calpers, sued the exchange and seven specialist trading firms over alleged trading abuses.
Calpers - which manages about $154bn (£90.5bn) and has about 1.5 million members - alleged that improper trading by the specialist firms went unchecked by the NYSE.
The NYSE declined to comment.
The Calpers lawsuit alleged that "NYSE orders were not being filled at the best available prices", to the benefit of the trading firms.
"The lawsuit alleges that the exchange looked the other way most of the time when these rules were violated," Calpers said.
A spokesman for the pension fund said it intended "to seek recovery for every single dollar lost."
On Tuesday, there was a further twist in the US mutual funds saga when it emerged that scandal-hit Putnam Investments has fired more staff.
Putnam, the fifth biggest US mutual fund, said that it had fired nine staff for improper trading.
The move brought the total number of Putnam traders dismissed since regulators began investigating the firm to 15.
Putnam and several other mutual funds are the subject of state and federal investigations into alleged "market-timing" - rapid-fire trading in fund shares by specialist investors to the detriment of long-term savers.
The investigations have shaken confidence in the mutual funds industry, which looks after the long-term savings of nearly half of all American households.