The Tesla boss has lost his title as the world’s richest person after a recent slide in the electric carmaker’s shares, the main driver of his wealth.
Tesla shares have fallen more than 20% since hitting a peak of more than $880 at the start of the year.
They suffered especially steep drops this week, tied to the firm’s controversial $1.5bn investment in Bitcoin.
The slide returned previous titleholder Amazon boss Jeff Bezos to the top spot on the rich list.
Experts say the risk of being associated with the notoriously volatile Bitcoin—the value of which has fallen sharply in recent days—may have led some Tesla investors to sell their shares, even if the firm has not been hurt by the declines.
“By Musk and Tesla aggressively embracing Bitcoin… investors are starting to tie Bitcoin and Tesla at the hip,” Wedbush Securities analyst Dan Ives told the BBC. “The recent 48-hour sell-off in Bitcoin and added volatility has driven some investors to the exits on this name in the near-term.”