(The Hill) — Sen. Ron Wyden, D-Ore., ripped Tesla and SpaceX CEO Elon Musk on Saturday after Musk proposed selling a percentage of his stock on Twitter. 

Musk’s earlier tweet appeared to be in response to a proposal that Wyden suggested aimed at taxing billionaires.

Musk is now the richest person in the world, a spot once held by Amazon founder Jeff Bezos

“Much is made lately of unrealized gains being a means of tax avoidance, so I propose selling 10% of my Tesla stock. Do you support this?” Musked asked in a poll posted on Twitter on Saturday.

“Whether or not the world’s wealthiest man pays any taxes at all shouldn’t depend on the results of a Twitter poll. It’s time for the Billionaires Income Tax,” Wyden, chair of the Senate Finance Committee, hit back in a statement issued later Saturday evening. 

Late last month, Wyden released a proposal to be included in Democrats’ social spending bill as a way to help pay for some of the initiatives proposed in the legislation. The tax proposal would tax the investment gains of billionaires annually. 

“We have a historic opportunity with the Billionaires Income Tax to restore fairness to our tax code, and fund critical investments in American families,” Wyden said in a statement at the time. 

The tax proposal would affect around 700 taxpayers who either have an income of over $100 million for at least three years in a row or have assets worth over $1 billion. 

In the proposal, tradable investment and non-tradable assets would be assessed differently. In the case of tradable investments, those affected under the policy would claim deductions on losses and pay taxes on investment gains each year. 

For scenarios that include real estate and other types of non-tradable assets, once taxpayers sell their assets, they could pay both regular capital gains taxes and an additional charge. 

The Joint Committee on Taxation’s (JCT) preliminary estimates of the policy indicated that it would have generated $557 billion over the span of a decade, however, it was ultimately not included in a framework proposed by the White House. 

Musk has previously slammed the policy, claiming that it would slowly start targeting other taxpayers later on. 

The House has yet to pass the $1.75 trillion social spending package built on the framework released by the White House. The lower chamber did pass a $1.2 trillion, bipartisan infrastructure passage on Friday.