Jin Lee/Bloomberg News

Lavish Wall Street bonuses, long the scorn of lawmakers and shareholders, have met a new foe: the Securities and Exchange Commission.

The agency on Wednesday proposed a crackdown on hefty compensation awarded at big banks, brokerage firms and hedge funds — a move intended to rein in pay packages that encouraged excessive risk-taking before the financial crisis.

The proposal would for the first time require Wall Street firms to file detailed accounts of their bonuses with the S.E.C., which could then ban any awards it deemed excessive. The rules would be aimed at top executives and hundreds of rank-and-file employees who receive incentive-based pay.

The move by regulators to have more say on Wall Street pay highlights the huge role financial institutions play in the economy. Although it would be highly unusual for the government to review the compensation of executives in most other industries, big banks pose a systemic risk to the system and in 2008 pushed the economy to the brink.

The S.E.C.’s plan, which closely resembles regulations already floated by the Federal Deposit Insurance Corporation, is mandated by the Dodd-Frank financial regulatory law. The proposed curbs on compensation ultimately will span seven federal agencies that regulate a wide range of financial firms.

The S.E.C.’s three Democratic commissioners voted Wednesday to move forward with the rules. Their decision came over the objection of the S.E.C.’s two Republican commissioners, who contended the agency was overstepping its authority.

The party-line vote is noteworthy in that it mirrors a similar partisan battle playing out on Capitol Hill. Republican lawmakers have threatened to slash the S.E.C.’s budget to keep it from enforcing the Dodd-Frank act, a product of the previous Democrat-controlled Congress.

Troy A. Paredes, a Republican commissioner on the S.E.C., argued that the agency was “not well-equipped to prescribe rules that dictate the specifics of how individuals must be paid.” The restrictions, Republican commissioners warned, could keep firms from recruiting star employees.

Even Mary L. Schapiro, the S.E.C.’s chairwoman, acknowledged that the agency might tweak its proposal down the road.

“This is an area where we want to be very attuned to unintended consequences,” she said in a statement. “As with any such undertaking, there is a challenge involved in finding common means to appropriately address Congress’s mandate.”

But Congress left little wiggle room for the S.E.C when writing the Dodd-Frank act. And significant changes appear unlikely now that other regulatory agencies have proposed similar rules.

“There could be a lot of pushback, but I don’t know how much leeway there is,” said David Lynn, a former top lawyer for the S.E.C.’s corporate finance division. “It’s like standing in front of a train — it’s coming,” said Mr. Lynn, who is now a partner at the law firm Morrison & Foerster.

Investor advocates and shareholders had a mixed reaction to the S.E.C. proposed compensation restrictions.

Amy Borrus, deputy director of the nonprofit Council of Institutional Investors, noted that “having to report bonuses may help provide that extra dollop of caution.”

But Anton V. Schutz, manager of the Burnham Financial Services fund, which holds stakes in several big banks, called the proposal “extreme” and said it would tax the S.E.C.’s already strained resources.

The S.E.C.’s plan is the culmination of a decade-long effort to temper Wall Street’s free-wheeling pay practices.

Lawmakers have taken aim at executive compensation as a leading cause of the financial crisis. Incentive-based pay packages, critics say, invited questionable risk-taking at the American International Group and the nation’s big banks.

During the crisis, the Obama administration appointed a so-called pay czar to set compensation limits and negotiate lower pay packages at financial firms and the two automakers the government bailed out, a move that caused much consternation among top traders and bankers.

Now, two years after the crisis, big Wall Street paydays are staging a comeback. Wall Street’s overall paychecks rose 6 percent in 2010, according to a recent report by the New York State Comptroller’s office. Cash bonuses are down, however, as regulators have nudged banks into awarding more stock and other deferred compensation.

The S.E.C. in January enacted “say on pay” rules that give shareholders a nonbinding vote on corporate salaries, bonuses and golden parachutes. The plan the S.E.C. announced on Wednesday goes even further.

For starters, it would require brokerage firms and investment advisers that manage more than $1 billion to file annual reports about incentive-based pay.

The S.E.C. would then halt any extravagant bonuses that expose the firm to a “material financial loss,” according to a summary of the proposal. The S.E.C. would scrutinize bonuses doled out to executive officers, directors and lower-level traders and bankers.

Financial firms that have $50 billion or more in assets — like Goldman Sachs and JPMorgan Chase — would face even tougher pay restrictions. The rules would require executive officers at these firms to defer half of their bonus for three years. If a firm suffered losses, the bonuses would be clawed back.

The proposal will now enter a 45-day public comment period, after which the S.E.C. will vote on a final version of the rules.