The electric-vehicle maker’s stock, which closed at US$580.99, surged 12% to US$649 at 5.16pm in New York, boosting the chief executive officer’s net worth to about US$36 billion, according to the Bloomberg Billionaires Index.

Musk, 48, owns about a fifth of Tesla’s outstanding stock, which comprises the bulk of his fortune, while his closely held Space Exploration Technologies Corp accounts for about US$14.6 billion.

Tesla’s shares have been on a roll since October, when the company posted a surprise third-quarter profit.

The firm’s market value is now above US$100 billion, and if it stays above that threshold for an extended period, Musk will be eligible to unlock the first chunk of a long-term compensation award that could net him more than US$50 billion if all performance targets are met.

He receives no salary or bonuses.