Elon Musk, the world’s wealthiest person, directed a series of insults at Bernie Sanders on Twitter after the U.S. senator repeated his call for billionaires to pay more in taxes.

Musk even raised the notion of selling more of his Tesla Inc. shares, which would require him to pay capital gains taxes.

The 80-year-old Sanders, who unsuccessfully sought the Democratic Party presidential nomination in 2016 and 2020, on Saturday tweeted that “we must demand that the extremely wealthy pay their fair share.” He didn’t mention Musk by name.

Musk, whose US$286 billion fortune has made him a target for supporters of a wealth tax, responded: “I keep forgetting that you’re still alive.”

In a subsequent tweet early Sunday, the chief executive officer of Tesla and SpaceX asked: “Want me to sell more stock, Bernie? Just say the word…”

Musk was still firing off tweets 11 hours later, saying Sanders “is a taker, not a maker.”

Musk offloaded almost US$7 billion worth of Tesla stock last week, helping push the automaker’s shares down 15 per cent. The stock fell 2.6 per cent at 9:36 a.m. Monday in New York.

The share disposals began after Musk polled Twitter users on whether he should sell. But some of the transactions were carried out under a trading plan he pre-arranged in September, well before he consulted his substantial social media following.

Musk also didn’t mention in his tweets that he has millions of stock options that must be exercised before they expire in August 2022. He said in September that he was likely to exercise “a huge block” of those options toward the end of this year.

Late last year, Musk confirmed he had moved from California to Texas, a state which levies no income tax. On Saturday, Musk tweeted that he’s been living in a small home in South Texas for the past two years. “Feels more homey to live in a small house,” he wrote.

Sanders, a Vermont independent who caucuses with Democrats, chairs the Senate Budget Committee and has long advocated for the wealthy to pay more taxes. In March, he tweeted that the amount of wealth Musk and Amazon.com Inc. co-founder Jeff Bezos had accumulated was “immoral.” 

Musk also recently chided U.S. Senator Ron Wyden, a Democrat from Oregon and chair of the Senate Finance Committee, who had pushed for a wealth tax on billionaires.