Up 177% in a single day! Moderna's (MRNA.US) cancer vaccine trial came to an end, blood laundered, and the shorters lost 5.5 billion US dollars

The Zhitong Finance App learned that Moderna's (MRNA.US) stock price soared at a record high, causing a heavy blow of 5.5 billion US dollars to shorters who bet that the vaccine manufacturer will continue to be sluggish for many years.

Moderna shares surged 177% on Wednesday after a personalized cancer vaccine developed in collaboration with partner MSD (MRK.US) helped reduce recurrence rates in advanced melanoma trials. According to S3 Partners LLC, the jump cost shorters approximately $5.5 billion in book losses, bringing their year-to-date losses in terms of market capitalization to about $7.7 billion.

Melanoma is the most serious type of skin cancer. According to the American Cancer Society, about 112,000 people are diagnosed in the US every year, and about 8,500 people die as a result.

The two companies said in a statement that they will discuss submitting listing applications to regulators and release relevant data at the upcoming medical conference. Moderna CEO Stefana Bonsell said in an interview that according to the results of the regulatory review, the product is expected to be approved for sale in 2027 as soon as possible.

Matthew Unterman, managing director of S3 Partners, said, “This is an unusually painful trend for Moderna's shorters,” and “today's market has fundamentally changed the risk-reward ratio for anyone maintaining a bearish position.”

Moderna bears suffer $5.5 billion loss due to melanoma trial results

Even before the melanoma trial results were announced, Moderna's stock price had risen 114% since this year — investors poured into the company in droves, hoping that its influenza vaccine would help the company get rid of its shrinking COVID-19 vaccination business and diversify. Moderna shares have been falling for the fourth year in a row as demand for COVID-19 vaccinations wanes, and is nearly 94% below its 2021 peak.

Wall Street analysts praised the trial's results as a huge potential benefit for Moderna. Needham analyst Joseph Stringer called the melanoma study a “landmark victory” for Moderna, saying it could turn the company's oncology business into the next growth engine.

Meanwhile, William Blair's Myles Minter raised its rating from “on par with the market” to “outperforming the market,” telling investors Moderna now has a clear outlook on diversifying its revenue away from the COVID-19 business.

The losses for shorters are likely to be even heavier. According to S3 Partners, the short balance as a share of Moderna's tradable shares (a measure of the number of tradable shares) was as high as 20% earlier this year, then fell back to around 14% as traders lifted some bearish bets.

Unterman said, “The reason why today's impact is even more profound is because shorting trades have previously been closed — around 20 million shares, or about a quarter of the positions, have been filled in 2026, so market fluctuations of this magnitude will force other bears to reevaluate or cut their positions.”