The Securities and Exchange Commission just ruled that large publicly held corporations must disclose the ratios of the pay of their top CEOs to the pay of their median workers. About time. In 1965, CEOs of America's largest corporations were paid, on average, 20 times the pay of average workers. Now, the ratio is over 300 to 1. It turns out the higher the CEO pay, the worse the firm does. Professor Michael J. Cooper of the University of Utah [and colleagues] recently found that companies with the highest-paid CEOs returned about 10 percent less to their shareholders than do their industry peers. So why aren't shareholders hollering about CEO pay? Because corporate law in the United States gives shareholders at most an advisory role. They can holler all they want, but CEOs don't have to listen. Larry Ellison, the CEO of Oracle, received a pay package in 2013 valued at $78.4 million, a sum so stunning that Oracle shareholders rejected it. That made no difference because Ellison controlled the board. In Australia, by contrast, shareholders have the right to force an entire corporate board to stand for re-election if 25 percent or more of a company's shareholders vote against a CEO pay plan two years in a row. Which is why Australian CEOs are paid an average of only 70 times the pay of the typical Australian worker. The new SEC rule requiring disclosure of pay ratios ... isn't perfect. Some corporations could try to game it. But the rule marks an important start.