Former Vice President Joe Biden, considered the most centrist candidate in the 2020 Democratic primary field, is now weighing a Wall Street tax to keep up with some of his far-left rivals who are hellbent on wealth taxes and soaking the rich — and the middle class — to pay for their giveaways.

According to Biden’s advisers, the plan would tax financial transactions like the sale of stocks and bonds, as first reported by the Washington Post.

Biden is reportedly under a lot of pressure to move further left on a number of policy issues, and he has somewhat embraced ideas like tax increases on the wealthy and big corporations. Of course, Biden has a long way to go to get anywhere near what his two biggest rivals, Vermont Sen. Bernie Sanders and Massachusetts Sen. Elizabeth Warren, have proposed.

The further-left Senators and 2020 hopefuls have each unveiled their own versions of different wealth taxes. Sanders just this week said “Billionaires should not exist,” and Warren has unveiled a pair of different wealth taxes.

According to the Washington Post report, an aide to Biden said his campaign is working on tax policy proposals but wouldn’t confirm the Wall Street tax. The campaign released a statement that said Biden will introduce new tax policies to show how he will pay for his proposed expansions to … government spending.

The former vice president “has and will continue to put forward details regarding how he will finance his biggest plans, because the stakes are too high not to be straightforward with the American people about how much they will cost and who will pay for them,” campaign spokesman Andrew Bates said in a statement.

Near the end of the Obama administration, Biden expressed interest in a transaction tax, and was impressed by how much money a Wall Street tax could raise.

According to the Congressional Budget Office, a financial transaction tax similar to what Sen. Brian Schatz, D-Hawaii, has proposed wouldn’t be as aggressive as Sanders’ plan, but would raise about $800 billion over the next decade.

Tax experts say Biden now considering this move signals just how much more aggressive Democrats are willing to be on raising taxes.

“To have a leading presidential candidate, who is considered a moderate, take a position so counter to Wall Street — that would be a big step, no question about it,” Americans for Tax Fairness Executive Director Frank Clemente said. “The vast majority of revenue it generates is from the wealthiest Americans, who have the most amount of money to contribute.”

Of course, a financial transaction tax on stocks and bonds also would hammer middle-class Americans who would feel the sting in their wallets much more painfully than the wealthy would.

Biden has also called for raising the corporate tax rate — which was slashed from 35% to 21% by the Tax Cuts and Jobs Act — from 21% to 28%, as well as increasing taxes on the top tax bracket.

Biden also wants to raise capital gains taxes on millionaires, end incentives to move corporate profits abroad and eliminate a loophole allowing heirs to receive capital gains tax-free, according to his campaign.

Though, Biden has stopped short of going all in on wealth tax proposals like Sanders’ and Warren’s.