Short sellers have sharply increased their positions against SpaceX, pushing bearish bets to nearly one-third of the company's publicly tradable shares as the stock continues to trade below its initial public offering price.

Data from S3 Partners shows that around 185 million SpaceX shares are currently sold short, equivalent to approximately 29% of the company's public float and representing roughly $25 billion in short positions. Just three weeks ago, short interest was estimated at only 40 million shares, or around 5% to 7% of the float.

Matthew Unterman, Head of Research at S3 Partners, said demand from short sellers has continued to grow since SpaceX went public, with many investors establishing speculative positions against the stock.

After a strong market debut, SpaceX shares have come under pressure in recent weeks. The stock has declined by around 20% in July and briefly fell below its IPO price of $135 on Wednesday for the first time. Shares were trading at approximately $131 on Thursday.

Investor attention is also turning to the company's upcoming lockup expirations, which are expected to significantly increase the number of shares available for trading. SpaceX's IPO included only about 5% of its estimated 13 billion outstanding shares, leaving most of the company's stock subject to lockup agreements, according to KeyBanc Capital Markets.

KeyBanc estimates that the first major lockup expiry could occur alongside the release of SpaceX's second-quarter earnings, making approximately 11% of outstanding shares eligible for sale.

Further lockup expirations are expected to follow, with additional portions of around 4% of outstanding shares scheduled for release beginning about 70 days after the IPO. Other share releases will be linked to performance-related milestones and the company's third-quarter earnings announcement.

Elon Musk's holding remains the largest individual stake, accounting for roughly 42% of shares outstanding. His shares are currently locked up until June 2027.

Meanwhile, SpaceX is preparing for its 13th Starship test flight on Thursday, an event that could have a significant impact on investor sentiment and the stock's near-term performance.

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