Tesla Motors CEO Elon Musk has seen his fortune take a billion dollar hit since November as slumping oil prices lower demand for alternative energy and electric cars.
Musk owns 28 million shares in electric car company Tesla Motors and almost 21 million shares in rooftop solar panel installer SolarCity, where he also serves as chairman.
The day before OPEC’s most recent meeting on November 26 Musk’s shares in the two companies were valued at a combined $8.6 billion.
The value of his shares have since fallen to about $7 billion, Marketwatch said.
With OPEC producers staunchly refusing any production cuts oil prices continue to hover around four year lows, depressing demand for alternative energy technologies.
Lower oil prices have also slashed prices at the gas pump, with gasoline now at about $2.50 per gallon in much of the United States.
Shares in Tesla have fallen 16 percent since late November while SolarCity shares drooped by 11 percent.
Both companies are based in California.