But the stock market is fickle, and Musk was back on top by the end of the day, at least according to Bloomberg, as Oracle gave up a bit of its earlier gains.

For those keeping score, the difference now is a billion, which isn’t much given the size of the figures: Musk’s $US384.2 billion ($578.4 billion) versus $US383.2 billion ($576.9 billion) for Ellison.

The duelling fortunes are so big each could fund the lifestyles of 5 million typical American families for a year, about the entire population of Florida, allowing them to all quit their jobs.

Or they could just tell all of South Africa to take a vacation for year and produce nothing, based on its gross domestic product.

The brief switch in the ranking came after a blockbuster earnings report from Oracle powered by multibillion dollar orders from customers as the artificial-intelligence race heats up.

Musk became the world’s richest person for the first time four years ago.

A big reason is his stake in a hot, but now cooling, electric car maker, Tesla.

Stock in the company has been moving in the opposite direction of Oracle’s, dropping 14 per cent so far this year.

Musk also controls several private companies, including rocket maker SpaceX, his artificial intelligence company xAI and the former Twitter, now called X.

Ellison owns about 40 per cent of Oracle, which means its surging stock added $150 billion to his net worth in little over a half-hour after the stock market opened.

The night before, after trading had closed, the company announced in an earnings report that it had struck more than $451 billion worth of new deals, including contracts with the OpenAI, Meta, Nvidia and Musk’s xAI.

It said that it now expects revenue from its cloud infrastructure business to jump 77 per cent to $27 billion this fiscal year then rise to $216 billion in four years after that.

Ellison said in an earnings call that Oracle would not just be making money from its computing centres that help build the next chatbots, but from the day-to-day running of those AI systems to run robots in factories, design drugs in laboratories, place bets in financial markets and automate legal and sales work at companies.

In other words, Ellison’s surge in wealth Wednesday morning reflected investor expectations that computers will take over many jobs now done by humans — and Oracle will benefit.

Or as the 81-year-old said on the call, “AI Changes Everything”.

Musk is hoping the same for Tesla and his own net worth, but he’s been struggling to convince investors.

The company had been promising a big turnaround in electric car sales after they fell sharply earlier this year, but the bounce back hasn’t happened.

Musk has been downplaying the bad numbers by trying to shift investors’ focus to Tesla’s other business of making robots and advances in the artificial intelligence behind its cars and robotaxis.

While he keeps talking up the Tesla future, though, the bad news keeps coming.

Tesla sales in the European Union plunged 40 per cent earlier this summer, the seventh month in row of drops, as customers balked at buying his cars after he took to X to support extreme right-wing politicians there.

The company has been losing market share in the US, too, as buyers angry with his embrace of Donald Trump have stayed away from Tesla showrooms.

Oracle stock closed Wednesday at $US328.33, a 36 per cent jump. Tesla was up less than one per cent at $US347.79.