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Octagon Capital Advisors LP

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13F filer, CIK 1839435, NEW YORK, NY

Octagon Capital Advisors LP reported $1,112,538,962 across 27 holdings for the quarter ended 2026-06-30, in a 13F-HR filed 2026-08-14. Its ten largest share positions make up 80.2% of the portfolio.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0001839435-26-000004

Period
2026-06-30
Reported value
$1.11B
Holdings
27
Top 10 weight
80.2%
New
5
Sold out
7

Largest buys vs the previous quarter

SecurityShares changeApprox. value
ABVXadded+316,000$42.1M
DFTXadded+510,000$24M
SMMTnew+1,250,000$18.2M
ANLnew+934,716$10.7M
PHVSadded+291,721$10.1M

Ranked by the share change valued at this quarter's implied price (value over shares in the 13F). A position sold out is valued at the previous quarter's price, its last report.

Largest sells vs the previous quarter

SecurityShares changeApprox. value
CNTAexited-750,000-$29.8M
KALVexited-1,450,000-$29.2M
TERNexited-530,000-$27.9M
TRVIreduced-1,170,000-$21.8M
KYMRreduced-115,000-$13.2M

Ranked by the share change valued at this quarter's implied price (value over shares in the 13F). A position sold out is valued at the previous quarter's price, its last report.

Holdings, Q2 2026

Share positions as resolved from 13F-HR 0001839435-26-000004, largest first. % of portfolio is the value over $1,089,547,362, the sum of the share positions whose value is usable for ratios (method).

SecurityHistorySharesValue% of portfolioChangeLatest eventTimeline
DNTHDIANTHUS THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: 1,746,667 shares; 2024Q4: 2,110,167 shares; 2025Q1: 2,341,667 shares; 2025Q2: 2,341,667 shares; 2025Q3: 2,416,667 shares; 2025Q4: 2,416,667 shares; 2026Q1: 1,946,667 shares; 2026Q2: 1,841,667 shares 1,841,667$180M16.48%-105,000Timeline
DFTXDEFINIUM THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: not reported; 2026Q1: 2,440,000 shares; 2026Q2: 2,950,000 shares 2,950,000$139M12.74%+510,000Timeline
ABVXABIVAX SAQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 1,230,000 shares; 2025Q2: 1,267,000 shares; 2025Q3: 1,325,000 shares; 2025Q4: 756,000 shares; 2026Q1: 677,000 shares; 2026Q2: 993,000 shares 993,000$132M12.15%+316,000Timeline
COGTCOGENT BIOSCIENCES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: 1,305,000 shares; 2024Q4: 2,763,000 shares; 2025Q1: 2,763,000 shares; 2025Q2: 2,763,000 shares; 2025Q3: 2,874,111 shares; 2025Q4: 2,350,000 shares; 2026Q1: 2,350,000 shares; 2026Q2: 2,350,000 shares 2,350,000$90.9M8.35%0Timeline
ALMSALUMIS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 2,530,700 shares; 2026Q1: 2,830,700 shares; 2026Q2: 2,830,700 shares 2,830,700$79.7M7.31%0Timeline
AVBPARRIVENT BIOPHARMA INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: 1,976,387 shares; 2024Q4: 2,059,387 shares; 2025Q1: 2,059,387 shares; 2025Q2: 1,946,054 shares; 2025Q3: 1,971,054 shares; 2025Q4: 1,971,054 shares; 2026Q1: 1,971,054 shares; 2026Q2: 1,971,054 shares 1,971,054$68.5M6.28%0Timeline
TSHATAYSHA GENE THERAPIES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: 4,572,222 shares; 2024Q4: 10,450,000 shares; 2025Q1: 10,700,000 shares; 2025Q2: 12,592,500 shares; 2025Q3: 9,067,500 shares; 2025Q4: 8,859,911 shares; 2026Q1: 8,859,911 shares; 2026Q2: 9,693,244 shares 9,693,244$66M6.06%+833,333Timeline
BIOABIOAGE LABS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 1,598,000 shares; 2026Q1: 1,748,000 shares; 2026Q2: 1,748,000 shares 1,748,000$42.8M3.93%0Timeline
MIRMMIRUM PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: not reported; 2026Q1: 338,900 shares; 2026Q2: 338,900 shares 338,900$39.7M3.64%0Timeline
KYMRKYMERA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 266,000 shares; 2025Q3: 360,000 shares; 2025Q4: 535,000 shares; 2026Q1: 425,000 shares; 2026Q2: 310,000 shares 310,000$35.5M3.26%-115,000Timeline
AKTSAKTIS ONCOLOGY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: not reported; 2026Q1: 960,847 shares; 2026Q2: 960,847 shares 960,847$31M2.84%0Timeline
XENEXENON PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: not reported; 2026Q1: 490,000 shares; 2026Q2: 490,000 shares 490,000$29.6M2.71%0Timeline
PALIPALISADE BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 9,567,898 shares; 2026Q1: 10,276,317 shares; 2026Q2: 10,276,317 shares 10,276,317$21.5M1.97%0Timeline
OCULOCULAR THERAPEUTIX INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: 2,425,000 shares; 2024Q4: 2,425,000 shares; 2025Q1: 2,425,000 shares; 2025Q2: 2,425,000 shares; 2025Q3: 2,624,000 shares; 2025Q4: 2,623,600 shares; 2026Q1: 3,166,600 shares; 2026Q2: 2,075,000 shares 2,075,000$20.4M1.87%-1,091,600Timeline
IRONDISC MEDICINE INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: not reported; 2026Q1: 270,000 shares; 2026Q2: 270,000 shares 270,000$19.7M1.81%0Timeline
SMMTSUMMIT THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: not reported; 2026Q1: not reported; 2026Q2: 1,250,000 shares 1,250,000$18.2M1.67%newTimeline
PHVSPHARVARIS N VQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: 620,470 shares; 2024Q4: 778,000 shares; 2025Q1: 769,815 shares; 2025Q2: 672,595 shares; 2025Q3: 722,595 shares; 2025Q4: 671,465 shares; 2026Q1: 165,000 shares; 2026Q2: 456,721 shares 456,721$15.8M1.45%+291,721Timeline
ANLADLAI NORTYE GROUP LTDQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: not reported; 2026Q1: not reported; 2026Q2: 934,716 shares 934,716$10.7M0.99%newTimeline
DTILPRECISION BIOSCIENCES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 1,917,995 shares; 2026Q1: 2,236,732 shares; 2026Q2: 1,350,000 shares 1,350,000$10.6M0.97%-886,732Timeline
DBVTDBV TECHNOLOGIES S AQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 1,018,021 shares; 2025Q3: 1,018,021 shares; 2025Q4: 574,200 shares; 2026Q1: 574,200 shares; 2026Q2: 574,200 shares 574,200$9.42M0.86%0Timeline
FTHFAETH THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: not reported; 2026Q1: not reported; 2026Q2: 361,010 shares 361,010$9.03M0.83%newTimeline
GYREGYRE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: not reported; 2026Q1: not reported; 2026Q2: 954,416 shares 954,416$6.29M0.58%newTimeline
TRVITREVI THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 3,322,000 shares; 2025Q2: 3,672,000 shares; 2025Q3: 2,815,000 shares; 2025Q4: 2,815,000 shares; 2026Q1: 1,485,000 shares; 2026Q2: 315,000 shares 315,000$5.87M0.54%-1,170,000Timeline
UNCYUNICYCIVE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 1,000,000 shares; 2025Q3: 1,000,000 shares; 2025Q4: 1,000,000 shares; 2026Q1: 1,000,000 shares; 2026Q2: 1,000,000 shares 1,000,000$4.69M0.43%0Timeline
CNTXCONTEXT THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: not reported; 2026Q1: 5,250,000 shares; 2026Q2: 3,050,000 shares 3,050,000$1.69M0.16%-2,200,000Timeline
GOSSGOSSAMER BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: 9,187,883 shares; 2024Q4: 18,350,000 shares; 2025Q1: 18,350,000 shares; 2025Q2: 18,350,000 shares; 2025Q3: 17,050,000 shares; 2025Q4: 13,915,371 shares; 2026Q1: 7,750,000 shares; 2026Q2: 7,750,000 shares 7,750,000$1.28M0.12%0Timeline

Options

Puts and calls, as filed. The amount and value describe the underlying shares, not the option premium, so they stay out of % of portfolio (H5).

SecurityTypeAmountValueChange
ERASCA INCERASCA INC CALLcall1,255,000$23Mnew

Sold out in Q2 2026

Positions in the previous quarter's report that this quarter's report no longer lists.

SecurityShares beforeValue beforeType
CNTACENTESSA PHARMACEUTICALS PLC750,000$29.8Mshares
KALVKALVISTA PHARMACEUTICALS INC1,450,000$29.2Mshares
TERNTERNS PHARMACEUTICALS INC530,000$27.9Mshares
BBOTBRIDGEBIO ONCOLOGY THERAPEUT719,000$6.44Mshares
LXEOLEXEO THERAPEUTICS INC1,100,000$6.31Mshares
CATXPERSPECTIVE THERAPEUTICS INC791,555$3.3Mshares
EVMNEVOMMUNE INC143,472$3.3Mshares

How Q2 2026 was built

Available 13F filings of this filer for the quarter and their roles: the base report is the latest original or restatement, NEW HOLDINGS amendments filed after it are added (method).

FilingRoleAmendmentFiledAcceptedIngested
13F-HR 0001839435-26-000004 base2026-08-14acceptance time not in the bulk data set