Short sellers are rapidly increasing their bets against SpaceX, driving bearish positioning to nearly one-third of the company’s public float as the struggling stock hovers around its IPO price.

About 185 million SpaceX shares are now sold short, representing roughly 29% of the company’s publicly tradable float and about $25 billion in bearish wagers, according to S3 Partners. The position has ballooned from an estimated 40 million shares, or roughly 5% to 7% of the float, just three weeks ago.

“We are seeing continuous demand from short sellers building speculative positions since the IPO,” Matthew Unterman, head of research at S3, told CNBC.

The surge in short interest comes as SpaceX shares have struggled after an initially strong debut. The stock has fallen about 20% in July and briefly slipped below its $135 IPO price on Wednesday for the first time. The stock last traded around $136 apiece.

The bearish positioning comes ahead of a closely watched lockup schedule that could substantially increase the number of shares available for trading over the coming months. SpaceX’s initial public float represented only about 5% of its roughly 13 billion shares outstanding, leaving the vast majority of stock still subject to lockup restrictions, according to KeyBanc Capital Markets,

KeyBanc estimated the first major unlock could come around the company’s second-quarter earnings report, when about 11% of outstanding shares may become eligible for sale.

Additional tranches of roughly 4% each are scheduled to be released beginning around day 70 after the IPO, followed by further unlocks tied to performance milestones and third-quarter earnings, the firm said.

The largest block remains Elon Musk’s stake, representing about 42% of shares outstanding, which is locked up until June 2027.

The company’s 13th Starship test flight is slated for Thursday, an catalyst that could influence sentiment toward the shares.