That's a lot of ammunition for those pushing for tighter controls over executive compensation.
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"Maybe CEOS won't be bothered, but I think workers will," said Dana Lime, product manager at NerdWallet. "This will hurt morale and to some extent productivity."
Perhaps as importantly, the numbers will stoke the debate over the SEC plan, which in turn was guided by the Dodd-Frank reform act.
(Read more: CEO Pay: Another statistic coming for investors)
SEC officials have battled over the plan's merits, with proponents saying it will tell shareholders whether company heads are performing up to their level of pay, while opponents believe there is no other purpose to the law than "to shame CEOs," as Republican commissioner Michael Piwowar described it.
In a statement to Reuters, Piwowar said "the shame from this rule should not be put on CEOS—it should be put on the five of us," he said. "Shame on us for putting special interests ahead of investors."
According to NerdWallet's numbers, which were gleaned from proxy statements, government reports and data firm BrightScope, Wal-Mart leads the disparity, with CEO Mike Duke having a retirement nest egg more than 6,000 times the size of his average worker's 401(k) plan.
(Read more: 10 ways to get your retirement plan back on track)
Duke's compensation—including salary and other forms—comes to $20.7 million a year, which is 836 times larger than the average non-manager compensation and 305 times the average manager compensation, NerdWallet said.
Those numbers don't tell the whole story, said Wal-Mart spokeswoman Brooke Buchanan.
"Mike has been with the company since 1996—for nearly 20 years. He's been voluntarily contributing to the deferred contribution (plan) since then, so you can imagine when you're working for a company for a while, the number gets higher," she said.