Dianthus Therapeutics Is Up 320% in a Year. One Major Investor Just Reduced Its Stake but Still Seems Bullish

Octagon Capital Advisors cut its stake in Dianthus Therapeutics(NASDAQ:DNTH) by 470,000 shares, an estimated $27.22 million trade based on quarterly average pricing, according to a May 15, 2026 SEC filing.

What happened

According to a SEC filing dated May 15, 2026, Octagon Capital Advisors reduced its holding in Dianthus Therapeutics by 470,000 shares during the first quarter. The estimated value of the shares sold was $27.22 million, based on the average closing price for the quarter. The quarter-end value of the remaining stake rose by $63.77 million, a change reflecting both share sales and stock price appreciation.

What else to know

Octagon Capital Advisors’ post-sale stake in Dianthus Therapeutics represents 18.08% of its 13F assets under management Top holdings after the filing:

NASDAQ: DNTH: $163.36 million (18.1% of AUM) NASDAQ:COGT: $90.45 million (10.0% of AUM) NASDAQ:ABVX: $75.38 million (8.3% of AUM) NASDAQ:ALMS: $62.36 million (6.9% of AUM) NASDAQ:DFTX: $46.12 million (5.1% of AUM) As of May 14, 2026, shares of Dianthus Therapeutics were priced at $85.34, up about 320% over the past year, compared to a 25% gain from the S&P 500.

Company Overview

Metric Value Price (as of market close 2026-05-14) $85.34 Market Capitalization $4 billion Revenue (TTM) $2 million Net Income (TTM) ($162.3 million)

Company Snapshot

Dianthus Therapeutics develops novel monoclonal antibody therapies targeting severe autoimmune and inflammatory diseases. The firm operates a clinical-stage biotechnology business model focused on the research and development of proprietary biologic drug candidates. It serves patients with severe autoimmune and inflammatory disorders.

Dianthus Therapeutics, Inc. is a clinical-stage biotechnology company based in New York City, specializing in the development of monoclonal antibody therapies for severe immune-mediated diseases. The company leverages proprietary research to advance its pipeline, aiming to address unmet medical needs in neuromuscular and inflammatory conditions.

What this transaction means for investors

Even after trimming 470,000 shares, Dianthus still remained Octagon Capital Advisors’ largest disclosed position at more than 18% of 13F assets, which says a lot about the fund’s conviction in the company’s long-term autoimmune pipeline.

The bigger story is that Dianthus keeps hitting operational milestones Earlier this month, management said it reached an early “GO” decision in its Phase 3 CAPTIVATE trial after identifying 20 confirmed responders before even reaching the planned 40-patient threshold. The company also said its generalized myasthenia gravis Phase 3 study remains on track to begin in mid-2026, with top-line results expected in the second half of 2028.

Financially, Dianthus appears well-capitalized. The company exited March with roughly $1.2 billion in cash and investments, enough runway into 2030, after raising about $719 million in a public offering earlier this year. The key question now is whether Dianthus can translate promising early efficacy into late-stage success before competition in autoimmune biologics intensifies.

Story Continues

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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.

Dianthus Therapeutics Is Up 320% in a Year. One Major Investor Just Reduced Its Stake but Still Seems Bullish was originally published by The Motley Fool

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