He may have picked a really ineffective time to do it, given America’s accelerating economic boom and near-record employment, and rising wages, but that isn’t stopping U.S. Senator Bernie Sanders from challenging four of the nation’s most prominent CEOs over their compensation policies.

In a series of letters, the Democratic icon from Vermont, and failed presidential candidate in 2016, called out Amazon CEO Jeff Bezos, Walmart CEO Doug McMillon, McDonald’s CEO Steve Easterbrook, and Walt Disney CEO Bob Iger, inviting the four to come to Washington, D.C., on July 16 to participate in a live-streamed “town hall” meeting during which they would be grilled to justify how much they are paid.

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“I really hope [the CEOs] have the guts to sit on a panel with their own employees and explain why it’s acceptable that they receive huge compensation packages while their very own workers are struggling to put food on the table,” Sanders said in an interview with CNN. “I hope they have the courage to do so. The invitation is sincere.” There was no early word on whether any of the chiefs would accept.

CEO-to-employee pay ratios have been a major plank in the Sanders platform for a long time, and he made income inequality his biggest issue to rally young workers (and voters) when he ran against Hillary Clinton for the Democratic presidential nomination in 2016.

The Obama administration adopted a new rule in 2015 requiring companies to report how the annual total compensation of the CEO compares with the median of the annual total compensation of their employees, the idea being to provide more insight into income inequality.

Sanders cherry-picked some good examples to buttress his point. Iger made $36.2 million for 2017, though shareholders in March rejected, in a non-binding vote, a plan that could reward him with up to $48.5 million a year over four years plus an equity grant worth about $100 million. McMillon made $22.2 million last year, and Easterbrook, $21.8 million. Bezos’s CEO compensation was listed as only $1.7 million, but as founder of Amazon and one of the world’s wealthiest individuals, he also sort of makes Sanders’ point.

But lost in this conversation as usual, (and as Chief Executive has noted many times before), is the fact that there are nearly 6 million companies in the United States, and fewer than 4,000 of them are public companies. Chief Executive does the largest annual survey of private company comp in the U.S. and — surprise — the numbers are a bit different than for these four. (For more information, go to www.ChiefExecutive.net/compreport).

US Private Company Median CEO Compensation (2016 actuals, the most recent data we have—we’re in the midst of our latest survey) was $361,558. At the same time, the Bureau of Labor Statistics pegs 2017 median earnings for all occupations at $50,620. That’s a CEO-to-worker pay ratio of 7.14.

More, to be sure, but nothing to broadcast, let alone livestream.

Read more: Average CEO Salary: Pay Has Largely Flatlined