Pay ratios: Who's getting named and shamed?

David Zaslav, president and chief executive officer of Discovery Communications.
Justin Solomon | CNBC
David Zaslav, president and chief executive officer of Discovery Communications.

CEOs making too much green may soon be feeling red in the face.

Starting in 2017, the Securities and Exchange Commission will require companies to share a metric comparing the CEOs' compensation to that of their median employee, the agency announced this week. Republicans and business groups have criticized the rule, which was included in Dodd-Frank five years ago, as "nakedly political," "more harmful than helpful" and an effort to "name and shame" business leaders.

Read MoreBreaking the biggest myth of CEO compensation

"In terms of comparable data, it's worthless," said Tom Quaadman, vice president of the Center for Capital Markets Competitiveness at the U.S. Chamber of Commerce. "The ratios tell you nothing about whether you should invest in a fast food chain or a Wall Street firm—neither ratio tells you how the company is doing."

But proponents contend that the metric will provide valuable information to investors about how companies manage human capital and will at least be useful for year-to-year comparisons. So which companies and industries are most likely to report especially high metrics? The Big Crunch looked at more than 2,300 publicly traded companies and compared average salary data for each industry to CEO compensation to see which companies should expect to get hit when the mud-flinging begins.

These ratios are likely different from what we'll see in 2017. For one thing, this doesn't include other forms of compensation like medical plans and perks, or international workers, both of which will show up in the final numbers. And these are only estimates based on industry means, while companies will have complete payroll data or statistical sampling to find the medians for their specific workforces. But they're a good start based on the available data.

The motion picture and sound recording industry comes to the top in this analysis mostly due to the $156.1 million in pay to Discovery Communications' David Zaslav—even that industry's relatively high pay could did not cancel out that sum. Discovery did not immediately respond to a request for comment.

The other industries with the highest gap are more what you would expect—companies with relatively unskilled workforces like big box stores, hotels and clothing makers. Companies with more employees in states with lower costs of living will also likely report higher ratios.

"Any industry you're going to see that has an hourly or seasonal workforce, like retail or fast food, I think they're going to have problems," said Quaadman. "Companies that have a wide presence overseas will also have different standards of living and compensation that they will have to deal with."

Read MoreCFOs: This year is going to be bad

Unlike most new regulations, which tend to disadvantage smaller companies, the ratio rule is expected to be most costly to implement for those larger international companies. Although keeping track of how much employees are getting in compensation seems like a simple task, those companies tend to have many employee data systems and have to figure out how to calculate the value of a pay package in different countries, according to the chamber.

Overall, companies with foreign operations are expected to pay about $714,000 each in initial compliance costs, while domestic-only operations will pay about $27,000—total costs for all affected companies will be more than $1.3 billion, according to the SEC.

Compensation is up, but less than expected

Historically, CEO compensation (including incentive payments and stock options) tends to boom with the stock market. While pay has continued to grow in recent years, it hasn't kept up with the S&P 500, according to data complied by the Economic Policy Institute, a think tank based in Washington.

"The stock market has revived to its prior high from before the recession, but CEO pay hasn't," said Lawrence Mishel, president of EPI. "It has become a little less linked, but they've recovered plenty relative to everybody else."

The reason for the shift isn't clear, but maybe public pressure against big pay packages is making a dent. If the new rule survives the coming legal challenges, we'll see if companies continue to hold down pay.

One thing's for sure—the days of executives quietly collecting far more than their employees may be coming to an end. They may continue to be highly paid, but they'll have to hear a lot more about it. According to Quaadman, that's not necessarily a good thing for companies or investors.

"One of the things my mother taught me growing up is never talk about salary, and the reason for that is all you're going to do is cause trouble and jealousy," said Quaadman. "This disclosure is going to put in place a system that is not going to help employee morale."

Correction: Total costs for all affected companies will be more than $1.3 billion. An earlier version misstated the figure.