Sen. Bernie Sanders (I-Vermont) introduced a bill to tax big companies whose employees need federal benefits to stay afloat. In doing so, he targeted Amazon founder/chief executive Jeff Bezos, who, said Sanders, “could play a profound role” by ensuring his employees earn a living wage. “This would not only improve lives for thousands of people at Amazon; it would send a message to every corporation in America that that’s where we should be going as a nation,” said the senator, whose bill is co-sponsored by Rep. Ro Khanna (D-California).

The Wall Street Journal reports that Sanders refers to his bill — the Stop Bad Employers by Zeroing Out Subsidies (shortened in a press release to the BEZOS Act) — as an end to “middle-class taxpayers’ subsidization of large, profitable companies owned by billionaires.” The bill is designed to “tax companies with 500 or more employees an amount equal to federal benefits received by their low-wage workers, effectively forcing them to pay more one way or another.”

In response, Amazon did not comment on the bill, but rather sang the praises of its “competitive pay, health insurance, disability insurance, retirement savings plans, company stock, and flexible schedules for new parents, along with opportunities to learn skills and further develop their careers … [and] posted new commentary on its corporate blog from three happy Amazon workers who contacted Sen. Sanders.”

Sanders has pointed to Amazon as “the epitome of wealth inequality in the U.S.,” and Amazon, in a “rare verbal rebuke,” said that Sanders made “inaccurate and misleading accusations.” The company has not commented on President Trump’s repeated criticisms.

Sanders asked current and former Amazon employees to share whether they have used “public assistance, such as food stamps, Medicaid or subsidized housing, in order to make ends meet” or if they struggled with “the demanding working conditions at Amazon.” Amazon head of global operations Dave Clark encouraged employees to respond to the survey.

On Tuesday, Amazon was briefly valued at $1 trillion for the first time, underlining Sanders’ argument about the company’s huge wealth. Bezos is also the world’s wealthiest person, “with a net worth of more than $166 billion, according to indexes that track individual wealth.”