Those betting against high-flying vaccine developer Moderna Inc. have taken their lumps this year with the biotech’s 370% rally costing short sellers almost $1.5 billion, according to financial analytics firm S3 Partners.

The Cambridge, Massachusetts-based biotech has boomed into a $36 billion behemoth amid excitement for its vaccine to treat the novel coronavirus.

Still, even with the stock’s parabolic move this week, it’s primed for a squeeze with short investor losses potentially outweighing overbought price conviction, S3 Partners managing director Ihor Dusaniwsky said in a note.

Moderna surged 6.9% to a record on Wednesday after early results from its Covid-19 vaccine candidate drew Wall Street praise. With the company set to start a final-stage study of the vaccine this month, excitement for the company and nerves for short sellers could push the stock even higher.

“There is $2.4 billion of buy-to-cover dry powder in this stock, once shorts begin to cover in size the buying pressure will jolt the stock price suddenly higher,” Dusaniwsky wrote Friday. Roughly 10% of Moderna shares available for trading are currently sold short, according to data compiled by S3 Partners.

The biotech’s (MRNA) 16% rally Friday, alongside peers, fueled it to a new record ahead of detailed results from a trial of AstraZeneca Plc and University of Oxford’s vaccine that are expected Monday. Moderna’s current five-day winning streak which has seen the stock jump by more than 50% is its best such move since April.