Under the proposal, companies would have the choice of calculating median employee pay from their total workforce or based on a sample of it.
The SEC opened the proposal to public comment for 60 days; it could be formally adopted sometime after that.
The move was called for by the 2010 financial overhaul law. Executive compensation is a hot-button issue with the public and in Congress, and it took on greater urgency during the financial crisis that began in the fall of 2008.
Outsize pay packages were blamed for encouraging disastrous risk-taking and short-term gain at companies at the expense of long-term performance.
Investor advocates, shareholder groups and union pension funds have pushed for reporting of the CEO-employee pay gap.
Reflecting the intense interest, the SEC received more than 20,000 comment letters on the issue.
Critics say the pay gap between CEOs and workers has widened sharply in recent decades. CEOs of major corporations earned 354 times more compensation last year than average American workers, double the gap in the early 1990s, according to the left-leaning Institute for Policy Studies think tank.
The SEC in 2011 gave shareholders at public companies the right to register their opinions on the executives’ pay at least once every three years, in a non-binding vote.
The SEC also voted 5-0 Wednesday to require registration with the agency for municipal advisers, who give advice to cities and towns that issue bonds on their bond sales and investing the proceeds.
Scandals in several municipalities, notably Jefferson County, Ala. — which filed what was the biggest U.S. municipal bankruptcy to that point in November 2011 — brought to light conflicts of interest and abuses by some municipal advisers.