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…