Last month, in the waning days of the administration of U.S. President Joe Biden, the SEC set a tight deadline of several days for demanding that Elon Musk pay a settlement or face civil charges relating to alleged securities violations during his $44 billion takeover of Twitter in 2022.

Musk broke the news himself in a social media post: "Oh Gary, how could you do this to me?” he wrote, referring to SEC Chair Gary Gensler.

He added a smiley-face emoji but attached a legal letter condemning the "improperly motivated” ultimatum: "We demand to know who directed these actions — whether it was you or the White House.”