Why This Fund Just Made a $55 Million Bet on Dianthus Amid a 350% Stock Rally

On May 15, 2026, Cormorant Asset Management disclosed a new position in Dianthus Therapeutics (NASDAQ:DNTH), acquiring 950,000 shares in an estimated $55.01 million trade based on quarterly average pricing.

What happened

According to a Securities and Exchange Commission (SEC) filing dated May 15, 2026, Cormorant Asset Management added a new position in Dianthus Therapeutics by purchasing 950,000 shares. The estimated transaction value was $55.01 million based on the average closing price for the quarter. The quarter-end position was valued at $79.72 million, capturing both the acquisition and subsequent price movement.

What else to know

• This was a new position for Cormorant, now accounting for 4% of reported 13F AUM as of March 31, 2026.
• Top five holdings post-filing:
  • NASDAQ:PRAX: $285.30 million (14.4% of AUM)
  • NASDAQ:BBOT: $160.01 million (8.1% of AUM)
  • NASDAQ:EYPT: $106.54 million (5.4% of AUM)
  • NASDAQ:EWTX: $102.69 million (5.2% of AUM)
  • NASDAQ:ERAS: $93.84 million (4.7% of AUM)
• As of May 14, 2026, shares of Dianthus Therapeutics were priced at $85.34, up 350% over the past year and vastly outperforming the S&P 500, which is instead up about 25%.

Company Overview

Company Snapshot

• Dianthus Therapeutics develops and advances novel monoclonal antibody therapies, with DNTH103 targeting severe autoimmune and inflammatory diseases such as generalized myasthenia gravis, multifocal motor neuropathy, and chronic inflammatory demyelinating polyneuropathy.
• The firm operates a clinical-stage biotechnology business model focused on research and development of proprietary biologic treatments.
• It serves patients suffering from rare and severe autoimmune and neuromuscular disorders, with primary customers expected to be healthcare providers, hospitals, and specialty clinics treating these conditions.

Dianthus Therapeutics, Inc. is a clinical-stage biotechnology company headquartered in New York City, specializing in the development of innovative monoclonal antibody therapies for severe autoimmune and inflammatory diseases. The company leverages a focused R&D approach to address unmet medical needs in rare neuromuscular conditions. Its strategy centers on advancing its lead candidate, DNTH103, through clinical trials to establish a competitive position in the specialty therapeutics market.

What this transaction means for investors

With Dianthus shares having surged 350% in the past year (and more than doubling last quarter alone), Cormorant still stepped in aggressively, suggesting the fund believes key clinical milestones could keep driving upside.

Dianthus has given investors plenty to watch recently. Earlier this month, the company said it reached an early “GO” decision in its Phase 3 CAPTIVATE trial after hitting responder targets faster than expected, something management framed as evidence that lead drug claseprubart may have “best-in-disease” potential. The company also said its generalized myasthenia gravis Phase 3 trial remains on track to begin in mid-2026, while additional data in multifocal motor neuropathy are expected later this year.

Dianthus ended the quarter with roughly $1.2 billion in cash after raising about $719 million earlier this year, giving it a projected runway into 2030. That kind of balance sheet strength matters in biotech, where funding risk can derail even promising pipelines.

After such a massive rally, expectations are now extremely high, but this filing suggests Dianthus may have more room to run.

Jonathan Ponciano has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.