Elon Musk is the world's first trillionaire. The initial public offering (IPO) of SpaceX added nearly $870 billion to his wealth. He has also amassed a fortune from Tesla, X, and other companies. Mr Musk is worth more than the world's next four richest people combined. Most of his wealth is tied up in stocks, rather than in cash. SpaceX's IPO was the largest in history. It raised $75 billion. It beat the previous record of $29.4 billion set by the oil company Aramco.

Elon Musk made his initial fortune with PayPal. He used money from this to start SpaceX in 2002. SpaceX now dominates the space travel industry. It launched more than half of all rockets last year. It also has 10,000 satellites in orbit. Musk's hope is to "make life multiplanetary". At the IPO, he said he wanted to take anyone who wanted to go, to the Moon or Mars "and ultimately beyond". He said: "Not just a few astronauts, I mean literally you."