Tesla remains Musk’s best-known business, but its fortunes are less directly tied to the government than SpaceX, his rocket-building company.

The feud reignited on Monday when Musk, who spent hundreds of millions on Trump's re-election, renewed his criticism of Trump's tax-cut and spending bill, which would eliminate subsidies for electric vehicle purchases that have benefited Tesla, the leading U.S. EV maker. That bill passed the Senate by a narrow margin midday Tuesday.

US President Donald Trump has made a bizarre threat to Elon Musk as the pair's wild feud explodes in front of the entire world. July 4 is traditionally a time of fireworks for the United States. But Elon Musk got the party started early.