U.S. Senator Bernie Sanders said he will introduce legislation to tax what he called the “obscene wealth gains” from billionaires during the coronavirus crisis.

Sanders, a self-described democratic socialist, made the announcement in a Twitter post Wednesday evening. Last year, while running for the Democratic nomination, Sanders embraced a proposal that would tax fortunes above $32 million at 1%, with an increasing rate that would top out at 8% over $10 billion.

"I will be introducing legislation tomorrow to tax the obscene wealth gains billionaires have made during the public health crisis," wrote Sanders on Twitter.

This time, he’s directed his focus to the profits billionaires have made since the Covid-19 crisis started. Sanders wrote that a 60% tax on the windfall gains from 467 billionaires between March 18 and Aug. 3 could raise more than $420 billion, which he said would be enough to allow Medicare to pay all out-of-pocket health-care expenses for everyone in the U.S. in the next year.

The senator’s office didn’t respond to a voice mail and email after normal business hours.

While the pandemic has left millions of Americans unemployed, the collective fortune of America’s billionaire class has surged since January, according to the Bloomberg Billionaires Index. The world’s wealthiest family, the Waltons of Walmart Inc., is richer than ever, and tech companies have become so powerful that some of the industry’s moguls had to defend their businesses to Congress last week. The market value of five of the largest American tech companies now represents almost a third of U.S. gross domestic product.

The world’s richest man, Amazon.com Inc.’s Jeff Bezos, has gained $74.9 billion this year alone, pushing his fortune to $190 billion. Elon Musk of Tesla Inc. has added $42.5 billion, taking his wealth to $70 billion, while Facebook Inc.’s Mark Zuckerberg is $16.2 billion richer, with a $94.5 billion net worth.

A Sanders tax on billionaire gains during the pandemic would need to get through Congress to take effect, which is virtually impossible given that Republicans control the Senate. And while the pandemic has renewed progressive demands to soak the rich, many Democrats have steered clear from backing a direct wealth tax. Presidential candidate Joe Biden’s proposed $4 trillion in new taxes avoids such a levy entirely and focuses instead on added income and payroll taxes for high-income individuals.

In his Twitter post, Sanders contrasted the gains made by the likes of Bezos and the Walton family with the U.S.’s continuing high unemployment and growing food insecurity.

“In all likelihood, in the midst of everything else, we are currently witnessing what is likely the greatest transfer of wealth from the middle class and the poor to the very rich in the modern history of this country,” Sanders wrote.

This article was provided by Bloomberg News.