On Polymarket, the probability that Musk will leave the administration by the end of the year spiked as high as 48% on Monday, the day Tesla shares plummeted.

Mr. Musk is fundamentally a creature of Silicon Valley, a scene that initiated an entire revolution in power dressing. The young masters of that universe dressed down to show that they were members of a new elite — one that refused to dress like the grown-ups they were about to topple. It was the defeat of the suit by the T-shirt.

Elon Musk on Monday highlighted the cost of federal spending on entitlement programs, the latest sign of the tech billionaire and presidential adviser’s focus to downsize the federal government amid fears of cuts to Social Security,

Elon Musk pushed debunked theories about Social Security on Monday while describing federal benefit programs as rife with fraud, suggesting they will be a primary target in his crusade to reduce government spending.

The billionaire entrepreneur, who is advising President Donald Trump, suggested that $500 billion to $700 billion in "waste" needed to be cut.