Siren, L.L.C. — 13F Holdings

2026 Q2  ·  127 Positions

2026 Q2 Portfolio Activity

In 2026 Q2, Siren, L.L.C. maintained a portfolio of 127 distinct positions. The most significant new addition was Abivax SA, now representing 1.55% of the total fund value. They heavily accumulated shares in Veradermics Inc, increasing the position by 1555.4%. The fund also reduced its exposure to Veradermics Inc by 98.7%.
Position History hover any row below to update
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Siren, L.L.C. Boston, MA Hedge Fund AUM $4,926M
PCA Score Concentration Risk
Risk ENB
Total Positions
127
Quarter
2026 Q2
Top Holding
SRRK (10.7%)
Top 10 Concentration
44.6%
Turnover Rate
23.4%
Sector HHI
0.18
Items per page:
Showing 1-50 of 127

Siren, L.L.C. Full Holdings List — 2026 Q2

Stock History Sector / Type Port % Prev % Rank / Prev Conviction
Freshness
Change % Change Influence Shares Mkt Value Avg Cost Price Held 1st Owned Source Source Date Date Reported
SRRK
Scholar Rock Ho...
Healthcare 10.66% 14.75% #1
Prev: #1
6.5
-1,250,000 -11.5%
P
S
9,575,013 $526,625,715
$12.43 +326.8%
$55.00 -3.5%
2024 Q3 13F Filing 2026-06-30 2026-08-13
KYMR
Kymera Therapeu...
Healthcare 6.81% 7.36% #2
Prev: #2
4.7
-251,000 -7.9%
P
S
2,935,830 $336,651,626 2024 Q3 13F Filing 2026-06-30 2026-08-13
ERAS
Erasca Inc
Healthcare 4.23% 5.04% #3
Prev: #3
3.2
153,535 1.4%
P
S
11,397,781 $208,807,348 2024 Q3 13F Filing 2026-06-30 2026-08-13
N/A
Veradermics Inc
Unknown 4.12% 2.64% #4 6
Prev: #10
4.1
150,000 10.0%
P
S
1,655,374 $203,511,680 13F Filing 2026-06-30 2026-08-13
TNGX
Tango Therapeut...
Healthcare 3.91% 3.28% #5 1
Prev: #6
4.1
522,259 9.2%
P
S
6,179,364 $193,166,919 2024 Q3 13F Filing 2026-06-30 2026-08-13
RVMD
Revolution Medi...
Healthcare 3.41% 3.00% #6 2
Prev: #8
1.9
-210,980 -19.0%
P
S
900,000 $168,552,000 2024 Q3 13F Filing 2026-06-30 2026-08-13
BCAX
Bicara Therapeu...
Healthcare 3.37% 3.20% #7
Prev: #7
1.8
-200,000 -3.4%
P
S
5,602,970 $166,352,179 2024 Q3 13F Filing 2026-06-30 2026-08-13
ARWR
Arrowhead Pharm...
Healthcare 2.83% 2.81% #8 1
Prev: #9
3.1
100,000 6.2%
P
S
1,715,476 $139,828,449 2024 Q3 13F Filing 2026-06-30 2026-08-13
ONC
BeOne Medicines...
Healthcare 2.68% 3.83% #9 4
Prev: #5
2.1
no change no change
P
S
465,000 $132,511,050 2024 Q3 13F Filing 2026-06-30 2026-08-13
EWTX
Edgewise Therap...
Healthcare 2.62% 3.87% #10 6
Prev: #4
1.0
-1,245,634 -28.1%
P
S
3,184,629 $129,391,476 2024 Q3 13F Filing 2026-06-30 2026-08-13
RYTM
Rhythm Pharmace...
Healthcare 2.55% 1.75% #11 9
Prev: #20
4.0
410,764 56.6%
P
S
1,136,275 $126,160,613 2025 Q1 13F Filing 2026-06-30 2026-08-13
LXRX
Lexicon Pharmac...
Healthcare 2.15% 1.92% #12 2
Prev: #14
1.9
no change no change
P
S
44,303,518 $106,328,443 2024 Q3 13F Filing 2026-06-30 2026-08-13
ELVN
Enliven Therape...
Healthcare 1.82% 0.81% #13 20
Prev: #33
3.7
1,028,185 137.8%
P
S
1,774,411 $90,051,358 2026 Q1 13F Filing 2026-06-30 2026-08-13
SYRE
Spyre Therapeut...
Healthcare 1.74% 1.14% #14 10
Prev: #24
2.7
150,000 18.3%
P
S
968,598 $85,992,130 2024 Q4 13F Filing 2026-06-30 2026-08-13
N/A
Parabilis Medic...
Unknown 1.66% #15
Prev: #—
4.2
2,992,259
NEW
2,992,259 $81,898,129 13F Filing 2026-06-30 2026-08-13
XENE
Xenon Pharmaceu...
Healthcare 1.61% 2.13% #16 5
Prev: #11
1.6
no change no change
P
S
1,318,564 $79,588,523 2024 Q3 13F Filing 2026-06-30 2026-08-13
SLDB
Solid Bioscienc...
Healthcare 1.55% 1.53% #17 4
Prev: #21
1.6
no change no change
P
S
7,690,405 $76,827,146 2024 Q3 13F Filing 2026-06-30 2026-08-13
ABVX
Abivax SA
Healthcare 1.55% #18
Prev: #—
4.1
576,000
NEW
576,000 $76,757,760 2026 Q2 13F Filing 2026-06-30 2026-08-13
N/A
Hemab Therapeut...
Unknown 1.55% #19
Prev: #—
4.1
2,086,834
NEW
2,086,834 $76,649,413 13F Filing 2026-06-30 2026-08-13
RCUS
Arcus Bioscienc...
Healthcare 1.51% 1.80% #20 3
Prev: #17
1.1
-586,647 -19.5%
P
S
2,420,430 $74,621,857 2024 Q3 13F Filing 2026-06-30 2026-08-13
COGT
Cogent Bioscien...
Healthcare 1.46% 1.82% #21 6
Prev: #15
2.6
150,000 8.8%
P
S
1,859,279 $71,954,097 2025 Q2 13F Filing 2026-06-30 2026-08-13
RLAY
Relay Therapeut...
Healthcare 1.38% #22
Prev: #—
4.1
3,650,000
NEW
3,650,000 $68,291,500 2026 Q2 13F Filing 2026-06-30 2026-08-13
TSHA
Taysha Gene The...
Healthcare 1.36% 1.09% #23 4
Prev: #27
2.5
1,016,666 11.5%
P
S
9,846,579 $67,055,203 2024 Q3 13F Filing 2026-06-30 2026-08-13
DFTX
Definium Therap...
Healthcare 1.35% 0.48% #24 20
Prev: #44
3.5
500,000 54.4%
P
S
1,419,493 $66,772,951 2026 Q1 13F Filing 2026-06-30 2026-08-13
STOK
Stoke Therapeut...
Healthcare 1.32% 1.80% #25 9
Prev: #16
1.5
no change no change
P
S
1,995,347 $65,287,754 2024 Q4 13F Filing 2026-06-30 2026-08-13
IRON
Disc Medicine I...
Healthcare 1.31% 1.75% #26 7
Prev: #19
1.0
-100,000 -10.1%
P
S
888,401 $64,977,649 2025 Q1 13F Filing 2026-06-30 2026-08-13
CYTK
Cytokinetics In...
Healthcare 1.31% 1.12% #27 2
Prev: #25
3.0
145,000 23.6%
P
S
758,952 $64,655,121 2024 Q3 13F Filing 2026-06-30 2026-08-13
SEPN
Septerna Inc
Healthcare 1.29% 1.33% #28 6
Prev: #22
1.0
-100,000 -5.0%
P
S
1,900,000 $63,631,000 2024 Q4 13F Filing 2026-06-30 2026-08-13
OLMA
Olema Pharmaceu...
Healthcare 1.23% 1.97% #29 17
Prev: #12
1.0
100,000 2.1%
P
S
4,856,949 $60,760,432 2025 Q4 13F Filing 2026-06-30 2026-08-13
CRNX
Crinetics Pharm...
Healthcare 1.08% 1.92% #30 17
Prev: #13
0.4
-482,848 -25.4%
P
S
1,420,788 $53,165,887 2024 Q3 13F Filing 2026-06-30 2026-08-13
N/A
Kailera Therape...
Unknown 0.99% #31
Prev: #—
3.9
2,214,286
NEW
2,214,286 $48,780,721 13F Filing 2026-06-30 2026-08-13
DYN
Dyne Therapeuti...
Healthcare 0.96% 1.12% #32 6
Prev: #26
0.9
-100,000 -4.5%
P
S
2,129,125 $47,287,866 2024 Q3 13F Filing 2026-06-30 2026-08-13
GPCR
Structure Thera...
Healthcare 0.95% 1.78% #33 15
Prev: #18
0.4
-455,731 -34.3%
P
S
872,967 $46,852,139 2025 Q3 13F Filing 2026-06-30 2026-08-13
TBLA
Taboola.com Ltd
Communication Services 0.85% 0.86% #34 2
Prev: #32
0.8
-1,546,085 -15.5%
P
S
8,423,410 $42,117,050 2024 Q3 13F Filing 2026-06-30 2026-08-13
PVLA
Palvella Therap...
Healthcare 0.80% 0.89% #35 4
Prev: #31
1.3
no change no change
P
S
257,485 $39,348,858 2025 Q4 13F Filing 2026-06-30 2026-08-13
SLN
Silence Therape...
Healthcare 0.74% 0.43% #36 15
Prev: #51
2.3
400,000 13.7%
P
S
3,311,438 $36,359,589 2024 Q3 13F Filing 2026-06-30 2026-08-13
DNLI
Denali Therapeu...
Healthcare 0.73% 0.74% #37 3
Prev: #34
1.3
no change no change
P
S
1,396,513 $35,918,314 2024 Q3 13F Filing 2026-06-30 2026-08-13
RELY
Remitly Global ...
Technology 0.70% 0.67% #38 3
Prev: #35
1.3
no change no change
P
S
1,543,271 $34,584,703 2024 Q3 13F Filing 2026-06-30 2026-08-13
CGEM
Cullinan Therap...
Healthcare 0.70% 0.47% #39 7
Prev: #46
3.3
700,000 58.7%
P
S
1,893,410 $34,478,996 2024 Q3 13F Filing 2026-06-30 2026-08-13
COF
Capital One Fin...
Financial Services 0.70% #40
Prev: #—
3.8
171,615
NEW
171,615 $34,429,401 2026 Q2 13F Filing 2026-06-30 2026-08-13
TRVI
Trevi Therapeut...
Healthcare 0.67% 0.59% #41 2
Prev: #39
1.3
no change no change
P
S
1,786,867 $33,325,070 2024 Q4 13F Filing 2026-06-30 2026-08-13
ORIC
Oric Pharmaceut...
Healthcare 0.66% 1.05% #42 13
Prev: #29
1.3
no change no change
P
S
2,998,192 $32,470,419 2024 Q3 13F Filing 2026-06-30 2026-08-13
GOOGL
Alphabet Inc
Communication Services 0.65% 0.52% #43 2
Prev: #41
2.8
24,297 37.0%
P
S
90,000 $32,163,300 2024 Q3 13F Filing 2026-06-30 2026-08-13
DBVT
Dbv Technologie...
Healthcare 0.62% 1.08% #44 16
Prev: #28
1.2
no change no change
P
S
1,857,362 $30,460,737 2025 Q4 13F Filing 2026-06-30 2026-08-13
ABSI
Absci Corp
Healthcare 0.58% 0.15% #45 30
Prev: #75
2.7
674,764 37.5%
P
S
2,474,764 $28,682,515 2026 Q1 13F Filing 2026-06-30 2026-08-13
SION
Sionna Therapeu...
Healthcare 0.54% 0.33% #46 9
Prev: #55
3.2
310,515 103.5%
P
S
610,515 $26,856,555 2025 Q1 13F Filing 2026-06-30 2026-08-13
RAPP
Rapport Therape...
Healthcare 0.54% 0.56% #47 7
Prev: #40
1.2
no change no change
P
S
641,469 $26,730,013 2024 Q3 13F Filing 2026-06-30 2026-08-13
AMLX
Amylyx Pharmace...
Healthcare 0.54% 0.47% #48 3
Prev: #45
2.7
250,586 20.4%
P
S
1,480,586 $26,591,325 2026 Q1 13F Filing 2026-06-30 2026-08-13
ANNX
Annexon Inc
Healthcare 0.52% 0.61% #49 11
Prev: #38
2.2
500,000 12.6%
P
S
4,458,646 $25,458,869 2026 Q1 13F Filing 2026-06-30 2026-08-13
MNPR
Monopar Therape...
Healthcare 0.51% 0.41% #50 3
Prev: #53
1.2
no change no change
P
S
270,118 $25,010,226 2025 Q4 13F Filing 2026-06-30 2026-08-13
Showing 1-50 of 127 holdings

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