Elon Musk made a bold claim on Twitter on Tuesday. The Tesla founder said he would "pay more taxes than any American in history this year."

Is the claim true? Only the IRS knows for certain who the largest taxpayer in US history is, but Forbes says Musk appears to be right.

"The eccentric billionaire (and the world's richest person) likely owes the federal government at least $8.3 billion for 2021," Forbes reports.

Business Insider projects Musk's tax bill is even higher when state taxes are included.

"Taxes on his stock, nearly a billion in Net Investment Income Tax, and the billions he likely owes California could add up to about $12 billion in total," report Jason Lalljee and Andy Kiersz.

CNBC, meanwhile, figured Musk's total tax bill was even higher—$15 billion.