SpaceX successfully launched its Starship rocket into orbit from the company's Starbase facility in South Texas last Friday evening, but the milestone has done little to halt the steep erosion of Elon Musk's personal wealth.

According to the Bloomberg Billionaires Index, Musk — who became the world's first trillionaire — is now poorer than he was before SpaceX priced its initial public offering last month. His net worth peaked at approximately $1.33 trillion on June 16 and has since fallen to $684 billion. The $600 billion-plus decline, registered in just over a month, exceeds the total net worth of every other individual ever listed among Bloomberg's 500 richest people, aside from Musk himself.

Shares of Space Exploration Technologies Corp., as SpaceX is formally known, reached a closing high of $201.80 on June 16 before tumbling 46% to a record low of $108.37. Downward pressure may intensify next month when as many as 911.5 million shares held by insiders and early backers become unlocked for trading — a standard post-IPO mechanism that allows pre-IPO shareholders to sell publicly for the first time, potentially expanding the available float substantially.

Short interest in the company surged to 219.3 million shares as of July 29, according to data from S3 Partners, a sharp increase from 23.3 million on June 16. That figure represents more than one-third of shares available for public trading. SpaceX is also scheduled to report quarterly earnings next week for the first time as a publicly listed company, an event that will provide investors their first detailed look at the company's financials since the IPO.

Tesla Inc. has been an additional drag on Musk's fortune. The electric vehicle manufacturer's shares have declined 17% since second-quarter results were released on July 22. Tesla reported $5.8 billion in capital expenditures, with Musk describing it as "a massive capex year." The company posted its first cash-negative quarter in two years, a development that overshadowed revenue growth driven by better-than-expected vehicle deliveries.

Tesla has signaled plans to roll out a range of new products, including Optimus humanoid robots, autonomous Cybercabs, and broader artificial intelligence initiatives. The company said it expects capital expenditures to exceed $25 billion for the full year.

Shares of the Austin-based automaker are down 36% from their December peak. The concurrent slide in both companies has compounded the impact on Musk's fortune, which is concentrated almost entirely in the two firms. According to Bloomberg's wealth index, Musk's Tesla stake is valued at $129 billion, while his SpaceX holdings are worth more than $550 billion.

Source: Fortune