Elon Musk's net worth fell $15 billion after Tesla's robotaxi event

• Tesla debuted its prototype Cybercab at Thursday's "We, Robot" event in Los Angeles.
• Tesla stock fell more than 9% on Friday, reducing Elon Musk's net worth.
• Though his net worth dropped by about $15 billion, Musk remains the world's richest man.

Tesla's robotaxi event , at which the company debuted the long-anticipated prototypes for its Cybercab and Robovan, failed to impress many investors and Wall Street analysts. The company's stock tumbled in the aftermath — and with it, CEO Elon Musk's net worth.

Musk's net worth — which is partly tied up in Tesla, as he holds about 13% of the company's stock — goes up and down along with the company's value. And on Friday, Tesla's stock sank more than 9% from $238.77 to $217.80 per share.

According to the Bloomberg Billionaires Index , updated after the close of trading in New York, Musk's net worth fell by $15 billion. With a total net worth of $240 billion, Musk remains the richest man on earth.

Forbes reported in July that Musk faced a similar financial hit after the "We, Robot" event was delayed from its original August date, and Tesla stock tumbled about 7%. The company's stock value had continued its downward trend through early August then rebounded in September — bringing Musk's net worth to more than that of McDonald's and Pepsi . However, Tesla shares had not yet returned to the year-to-date high they'd hit in July before the stock slumped again this week.

Musk will control more than 20% of Tesla shares if his massive pay package survives its ongoing legal challenges, which could increase his net worth.

Musk and representatives for Tesla did not immediately respond to requests for comment from Business Insider.

Business Insider reported that the "We, Robot" event left many Wall Street analysts with more questions than answers about Tesla's robotaxi fleet . Analysts criticized the lack of detail about the company's plan for self-driving vehicles and showed skepticism surrounding the proposed timelines for their widespread release. That lack of clarity and the absence of the long-promised, less-expensive Tesla could have contributed to the stock's decline.

"Heading into what might arguably have been the most highly anticipated product unveil in Tesla's history , we had a number of expectations of what the market might learn that we felt were consequential to the direction and debate around the stock," Business Insider reported Morgan Stanley analyst Adam Jonas, wrote in a Friday morning note to clients. "We were overall disappointed with the substance and detail of the presentation."

At the event, Musk said Tesla plans to roll out its autonomous Cybercabs "before 2027" and did not provide a timeline for the launch of its Robovan, which will seat 20. The company also revealed the latest prototypes for its humanoid Optimus robots , which danced, poured drinks, and posed for selfies during the event.

Musk said the robots will be " the biggest product ever, of any kind ."

In posts on X following the event, Musk highlighted the reviews of Tesla investors impressed with the company's vision for the future of autonomous taxis , including reposting a clip of Wedbush analyst Dan Ives describing Tesla as "front and center of the 4th Industrial Revolution."