SpaceX pulled off a successful launch last Friday evening at its Starbase facility in South Texas, sending its Starship rocket into orbit. It hasn’t stopped Elon Musk’s fortune from falling back to Earth.

The world’s first trillionaire is now poorer than he was before SpaceX’s initial public offering priced last month, according to the Bloomberg Billionaires Index.

Musk’s wealth, which peaked at about $1.33 trillion on June 16, now stands at $684 billion. The $600 billion-plus decline in just over a month exceeds the net worth of any other person who has ever been on Bloomberg’s list of the world’s 500 richest people, other than Musk himself.

Shares of Space Exploration Technologies Corp., as the company is formally known, hit a closing high of $201.80 on June 16, but have since tumbled 46% to a record low of $108.37. Next month as many as 911.5 million shares belonging to insiders and early backers will be unlocked, potentially putting more downward pressure on the price.

Short interest in the company rose to 219.3 million shares as of July 29, according to S3 Partners, up from 23.3 million on June 16. That’s more than one-third of those available for public trading. Next week SpaceX reports its quarterly earnings for the first time as a public company.