Because of his acquisition of Twitter, the Tesla CEO's fortune has decreased by half from its height of $340 billion.
Elon Musk has lost his title as the world's richest person as the value of his electric vehicle company Tesla continues to fall.
According to Forbes and Bloomberg, which track billionaire wealth, Musk has lost the top rank to France's Bernard Arnault, CEO of the luxury conglomerate LVMH.
Born in South Africa Musk, who just purchased Twitter, is the CEO of Tesla and its largest shareholder. Since Musk's initial offer for Twitter in April, the electric vehicle firm has lost more than half of its market value.
Tesla stock was trading at $340.79 (£275.27) on April 13, the day before Twitter reported in a regulatory filing that the billionaire had launched a $43.4 billion hostile proposal. Tesla's stock price has dropped by more than 50% since then, and it is now trading at around $160.
According to Forbes, further drops in the auto company's share price at the start of the week knocked off approximately $7 billion from Musk's fortune. It calculates that he is now worth approximately $177 billion, compared to Arnault's net worth of $188 billion.
Arnault temporarily surpassed Musk a week ago as a consequence of share price changes, before the Tesla CEO reclaimed the top place.
Musk has sold around $20 billion in Tesla stock since April to fund his acquisition of Twitter.
Tesla's market value has fallen as a result of dismal quarterly results and concerns about a disruption at one of its Shanghai operations.
Investors are concerned that Musk would be distracted by his other companies, including SpaceX and operating Twitter. He is also frequently chastised for some of the inflammatory tweets he delivers to his 121 million followers.