Elon Musk, the world's richest person, questions if money buys happiness. Studies suggest income boosts happiness, but with diminishing returns.

Musk, the richest man in the world wrote on X, the platform he owns that "money can't buy happiness," followed by a sad face emoji.

Elon Musk has spent recent days on his social media site X trying to explain why he exchanged so many emails with Jeffrey Epstein. The billionaire Tesla CEO insists that Epstein was the one pursuing him.

Prosecutors in Paris said they asked Elon Musk to appear for questioning after searching X's offices in as part of a probe into sexual deepfakes.

As with SpaceX, then, Mr Musk is gambling Tesla’s future on AI, and his belief that he can harness his existing businesses to dominate the technology. Plenty of doubters have scoffed at his grand ambitions before. But never has Mr Musk put so much on the line. ■

This latest round of the feud began after court filings in Musk's lawsuits against OpenAI and Apple became public. Jason Kwon, OpenAI's chief strategy officer, wrote that Musk and his AI company, xAI, produced almost no substantive internal documents during discovery, allegedly relying instead on disappearing messages.

Elon Musk is joining his space exploration and artificial intelligence ventures into a single company before a massive planned initial public offering for the business later this year.

Elon Musk's net worth potentially blasting off to another world thanks to SpaceX. CNBC's Robert Frank joins 'Squawk Box' with the details.

The move followed a yearlong investigation into X and escalated a wider standoff between European officials and American tech companies over the regulation of social media.

Tesla CEO Elon Musk said that even he has "fallen prey" to "the pixie dust" of seeing Apple or Google on a résumé.