Octagon Capital Advisors portfolio
Concentrated managerType not verifiedPortfolio as of Jun 30, 2026 (Q2 2026) · filed with the SEC on Aug 14, 2026 · data updated on Nov 5, 2026 · Q2 2026 13F (filing) ↗ · all its 13F filings ↗
A 13F shows the portfolio at quarter-end and is filed up to 45 days later: these are not real-time positions and they may have changed.
Octagon Capital Advisors reported a $1.1 bn portfolio of 26 positions to the SEC as of the end of Q2 2026. Its largest positions are DNTH, DFTX, ABVX. During the quarter it opened Summit Therapeutics and Adlai Nortye and exited BridgeBio Oncology Therapeutics.
Sections with a free account
What it reported after the quarter end (Q2 2026)
The 13F shows the portfolio as of Jun 30, 2026. Since then Octagon Capital Advisors has filed these own trades with the SEC (Form 4, when it owns more than 10% of a company or holds a role in it) and stakes above 5% (13D and 13G). It is not everything it did: only what it must report before the next 13F.
What changed this quarter
18 positions with a change (4 new, 4 added to, 6 trimmed, 4 sold); also, 3 exited through an acquisition or merger. 12 are listed here: those of 0.5 points of the portfolio or more (up to 12).
- Abivax+47%more sharesIncreased8.3% → 12.1%
- Definium Therapeutics+21%more sharesIncreased5.1% → 12.7%
- Summit Therapeutics+1.7 ppof portfolioNew— → 1.7%
- Trevi Therapeutics−79%fewer sharesReduced2.0% → 0.5%
- Kymera Therapeutics−27%fewer sharesReduced3.9% → 3.3%
- Adlai Nortye+1.0 ppof portfolioNew— → 1.0%
- Ocular Therapeutix−34%fewer sharesReduced3.0% → 1.9%
- Dianthus Therapeutics−5.4%fewer sharesReduced18.1% → 16.5%
- Pharvaris+177%more sharesIncreased0.5% → 1.4%
- Faeth Therapeutics+0.8 ppof portfolioNew— → 0.8%
- Precision Biosciences−40%fewer sharesReduced1.4% → 1.0%
- BridgeBio Oncology Therapeutics−0.6 ppof portfolioSold out0.7% → —
The figure on the right: for positions added to or trimmed, the change in the number of shares (%); for new and sold ones, the points of the portfolio moved (pp). Below, the portfolio weight before → after. Traded weight: what it bought or sold, excluding price effects.
Top holdings
- Dianthus TherapeuticsDNTH16.5%
- Definium TherapeuticsDFTX12.7%
- AbivaxABVX12.1%
- Cogent BiosciencesCOGT8.3%
- AlumisALMS7.3%
- Arrivent BiopharmaAVBP6.3%
- Taysha Gene TherapiesTSHA6.1%
- Bioage LabsBIOA3.9%
- Mirum PharmaceuticalsMIRM3.6%
- Kymera TherapeuticsKYMR3.3%
- Aktis OncologyAKTS2.8%
- Xenon PharmaceuticalsXENE2.7%
- Palisade BioPALI2.0%
- Ocular TherapeutixOCUL1.9%
- Disc MedicineIRON1.8%
“Since”: first quarter of the current run, unbroken until today. In the details, prices are the quarter-end prices of the quarters in which it added shares, per the 13F. The manager may have bought at any price within each quarter; the SEC only publishes the value at quarter end.
Portfolio by sector
- ● Health Care 100%
How its portfolio changed (8 quarters)
Q2 2026: 26
Q2 2026: 80%
Q2 2026: 9.4%
Traded turnover: the weight it bought plus the weight it sold in the quarter, divided by two, excluding price moves. The plain “turnover” in the header does include that effect. With a free account: the full history and sectors over time.
13F filings with amendments or confidential positions
- 13F Q1 2025 ↗filed May 15, 2025Amendment of May 16, 2025 (replaces the original) ↗
Declared options (1)
Besides stocks, Octagon Capital Advisors declared 1 call (they gain if it rises) with a notional of $23.0M. The 13F reports the value of the underlying shares, not the premium paid, so these figures look large and are not added to the portfolio. Nor does it say whether the option is bought or written, or its strike or expiry: it may be a hedge.
- CALLErascaERASnew this quarter$23.0M
Stakes above 5% (13D/13G)
Companies where this filer reported holding 5% or more of the shares. It is the figure from its latest filing on each one; history since December 2024.
How we classify it
Type not verified. It meets the portfolio criteria of a concentrated manager, but its type is not verified: we found no official document that is enough to say what kind of entity it is. It may be an investment firm, but also an adviser adding up client accounts, a bank or a family vehicle. It counts in the tallies like the rest; keep that in mind when reading it. How the type is assigned
Managers of a similar size
A 13F portfolio value between a third and three times this one, whatever the type of filer. It is not a comparison of what they hold.
- Vivo CapitalInvestment firm · $1.1 bn
- Bruni J V$1.1 bn
- Dock Street Asset Management$1.1 bn
- Alta Park Capital$1.1 bn
- Hook Mill Capital PartnersInvestment firm · $1.1 bn
- Heron Bay Capital Management$1.1 bn