The richest man in the world, Musk, has seen his wealth plunge almost $100 billion this year, the most on record.
The net worth of the 51-year-old, which peaked at $340 billion in November last year, plummeted to around $170 billion on Tuesday, after the stock market fell.
Musk's wealth was wiped out in one day by the decline in the electric vehicle maker's stock price.
Most of the tech mogul's wealth is derived from his stock holdings in companies like Musk's electric car company, and the social networking site. The company's shares have plummeted since the beginning of the year.
Musk's net worth was $13 billion higher than that of Arnault, the chairman of the world's largest maker of luxury goods.
According to the same index, Musk's net worth surpasses that of both Bezos and Gates.
Concerns of an economic downturn and the Federal Reserve's aggressive interest rate hikes have led to a broad selloff in the tech markets.
The country's strict Covid-zero stance, as well as whether Musk is able to focus on his role as CEO, is causing investors to worry.
The two companies did not respond to Insider's questions.