Siren, L.L.C. — 13F Holdings

2026 Q1  ·  132 Positions

2026 Q1 Portfolio Activity

In 2026 Q1, Siren, L.L.C. maintained a portfolio of 132 distinct positions. The most significant new addition was Cytokinetics Inc, now representing 1.12% of the total fund value. They heavily accumulated shares in Erasca Inc, increasing the position by 28.4%. Conversely, Siren, L.L.C. completely exited their position in Apellis Pharmaceuticals Inc.
Position History hover any row below to update
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Siren, L.L.C. Boston, MA Hedge Fund AUM $3,607M
PCA Score Concentration Risk
Risk ENB
Total Positions
132
Quarter
2026 Q1
Top Holding
SRRK (14.8%)
Top 10 Concentration
49.8%
Turnover Rate
23.4%
Sector HHI
0.18
Items per page:
Showing 1-50 of 132

Siren, L.L.C. Full Holdings List — 2026 Q1

Stock History Sector / Type Port % Prev % Rank / Prev Conviction Change % Change Influence Shares Mkt Value Avg Cost Price Held 1st Owned Source Source Date Date Reported
SRRK
Scholar Rock Ho...
Healthcare 14.75% 14.22% #1
Prev: #1
7.0 no change no change
P
S
10,825,013 $532,157,639
$12.43 +302.2%
$49.16 +1.7%
2024 Q3 13F Filing 2026-03-31 2026-05-14
KYMR
Kymera Therapeu...
Healthcare 7.36% 7.63% #2
Prev: #2
4.9 -100,000 -3.0%
P
S
3,186,830 $265,431,071 2024 Q3 13F Filing 2026-03-31 2026-05-14
ERAS
Erasca Inc
Healthcare 5.04% 0.97% #3 28
Prev: #31
5.5 2,486,997 28.4%
P
S
11,244,246 $181,931,900 2024 Q3 13F Filing 2026-03-31 2026-05-14
EWTX
Edgewise Therap...
Healthcare 3.87% 3.35% #4
Prev: #4
2.5 -99,727 -2.2%
P
S
4,430,263 $139,553,285 2024 Q3 13F Filing 2026-03-31 2026-05-14
ONC
BeOne Medicines...
Healthcare 3.83% 4.53% #5 2
Prev: #3
2.5 -35,000 -7.0%
P
S
465,000 $138,091,050 2024 Q3 13F Filing 2026-03-31 2026-05-14
TNGX
Tango Therapeut...
Healthcare 3.28% 2.16% #6 6
Prev: #12
1.3 -2,508,269 -30.7%
P
S
5,657,105 $118,346,637 2024 Q3 13F Filing 2026-03-31 2026-05-14
BCAX
Bicara Therapeu...
Healthcare 3.20% 2.62% #7 1
Prev: #8
3.3 586,001 11.2%
P
S
5,802,970 $115,421,073 2024 Q3 13F Filing 2026-03-31 2026-05-14
RVMD
Revolution Medi...
Healthcare 3.00% 3.17% #8 3
Prev: #5
1.7 -224,095 -16.8%
P
S
1,110,980 $108,042,805 2024 Q3 13F Filing 2026-03-31 2026-05-14
ARWR
Arrowhead Pharm...
Healthcare 2.81% 2.97% #9 2
Prev: #7
3.1 115,000 7.7%
P
S
1,615,476 $101,290,345 2024 Q3 13F Filing 2026-03-31 2026-05-14
N/A
Veradermics Inc
Unknown 2.64% #10
Prev: #—
4.6 1,505,374
NEW
1,505,374 $95,064,368 13F Filing 2026-03-31 2026-05-14
XENE
Xenon Pharmaceu...
Healthcare 2.13% 1.09% #11 18
Prev: #29
3.9 505,803 62.2%
P
S
1,318,564 $76,674,497 2024 Q3 13F Filing 2026-03-31 2026-05-14
OLMA
Olema Pharmaceu...
Healthcare 1.97% 2.46% #12 3
Prev: #9
3.3 1,456,249 44.1%
P
S
4,756,949 $70,926,110 2025 Q4 13F Filing 2026-03-31 2026-05-14
CRNX
Crinetics Pharm...
Healthcare 1.92% 2.09% #13 2
Prev: #15
3.3 396,000 26.3%
P
S
1,903,636 $69,140,060 2024 Q3 13F Filing 2026-03-31 2026-05-14
LXRX
Lexicon Pharmac...
Healthcare 1.92% 1.34% #14 11
Prev: #25
2.8 5,384,615 13.8%
P
S
44,303,518 $69,113,488 2024 Q3 13F Filing 2026-03-31 2026-05-14
COGT
Cogent Bioscien...
Healthcare 1.82% 1.73% #15 3
Prev: #18
1.2 80,000 4.9%
P
S
1,709,279 $65,790,149 2025 Q2 13F Filing 2026-03-31 2026-05-14
STOK
Stoke Therapeut...
Healthcare 1.80% 2.13% #16 2
Prev: #14
1.2 -252,000 -11.2%
P
S
1,995,347 $64,968,498 2024 Q4 13F Filing 2026-03-31 2026-05-14
RCUS
Arcus Bioscienc...
Healthcare 1.80% 2.14% #17 4
Prev: #13
1.7 no change no change
P
S
3,007,077 $64,952,863 2024 Q3 13F Filing 2026-03-31 2026-05-14
GPCR
Structure Thera...
Healthcare 1.78% 2.24% #18 7
Prev: #11
3.2 250,000 23.2%
P
S
1,328,698 $64,043,244 2025 Q3 13F Filing 2026-03-31 2026-05-14
IRON
Disc Medicine I...
Healthcare 1.75% 2.34% #19 9
Prev: #10
1.7 no change no change
P
S
988,401 $63,198,360 2025 Q1 13F Filing 2026-03-31 2026-05-14
RYTM
Rhythm Pharmace...
Healthcare 1.75% 1.60% #20 1
Prev: #21
3.2 225,536 45.1%
P
S
725,511 $63,097,692 2025 Q1 13F Filing 2026-03-31 2026-05-14
SLDB
Solid Bioscienc...
Healthcare 1.53% 1.29% #21 6
Prev: #27
1.6 no change no change
P
S
7,690,405 $55,370,916 2024 Q3 13F Filing 2026-03-31 2026-05-14
SEPN
Septerna Inc
Healthcare 1.33% 1.66% #22 3
Prev: #19
1.5 no change no change
P
S
2,000,000 $48,060,000 2024 Q4 13F Filing 2026-03-31 2026-05-14
CNTA
Centessa Pharma...
Healthcare 1.16% 3.00% #23 17
Prev: #6
0.5 -2,974,053 -73.8%
P
S
1,053,464 $41,843,590 2024 Q3 13F Filing 2026-03-31 2026-05-14
SYRE
Spyre Therapeut...
Healthcare 1.14% 0.80% #24 10
Prev: #34
1.5 no change no change
P
S
818,598 $41,290,083 2024 Q4 13F Filing 2026-03-31 2026-05-14
CYTK
Cytokinetics In...
Healthcare 1.12% #25
Prev: #—
3.9 613,952
NEW
613,952 $40,465,576 2024 Q3 13F Filing 2026-03-31 2026-05-14
DYN
Dyne Therapeuti...
Healthcare 1.12% 2.04% #26 10
Prev: #16
0.4 -1,273,816 -36.4%
P
S
2,229,125 $40,414,036 2024 Q3 13F Filing 2026-03-31 2026-05-14
TSHA
Taysha Gene The...
Healthcare 1.09% 1.66% #27 7
Prev: #20
0.9 -1,300,000 -12.8%
P
S
8,829,913 $39,469,711 2024 Q3 13F Filing 2026-03-31 2026-05-14
DBVT
Dbv Technologie...
Healthcare 1.08% 1.06% #28 2
Prev: #30
1.4 no change no change
P
S
1,857,362 $38,800,292 2025 Q4 13F Filing 2026-03-31 2026-05-14
ORIC
Oric Pharmaceut...
Healthcare 1.05% 0.25% #29 27
Prev: #56
3.4 1,990,617 197.6%
P
S
2,998,192 $37,987,092 2024 Q3 13F Filing 2026-03-31 2026-05-14
ENGN
enGene Holdings...
Healthcare 0.99% 0.90% #30 2
Prev: #32
3.4 1,916,895 57.5%
P
S
5,253,159 $35,774,013 2025 Q4 13F Filing 2026-03-31 2026-05-14
PVLA
Palvella Therap...
Healthcare 0.89% 0.23% #31 27
Prev: #58
3.4 182,485 243.3%
P
S
257,485 $32,095,505 2025 Q4 13F Filing 2026-03-31 2026-05-14
TBLA
Taboola.com Ltd
Communication Services 0.86% 1.37% #32 8
Prev: #24
1.3 no change no change
P
S
9,969,495 $30,905,435 2024 Q3 13F Filing 2026-03-31 2026-05-14
ELVN
Enliven Therape...
Healthcare 0.81% #33
Prev: #—
3.8 746,226
NEW
746,226 $29,252,059 2026 Q1 13F Filing 2026-03-31 2026-05-14
DNLI
Denali Therapeu...
Healthcare 0.74% 0.69% #34 2
Prev: #36
1.3 no change no change
P
S
1,396,513 $26,813,050 2024 Q3 13F Filing 2026-03-31 2026-05-14
RELY
Remitly Global ...
Technology 0.67% 0.67% #35 2
Prev: #37
0.8 -75,000 -4.6%
P
S
1,543,271 $24,183,057 2024 Q3 13F Filing 2026-03-31 2026-05-14
GLTO
Damora Therapeu...
Healthcare 0.65% #36
Prev: #—
3.8 900,000
NEW
900,000 $23,310,000 2026 Q1 13F Filing 2026-03-31 2026-05-14
ZURA
Zura Bio Ltd
Healthcare 0.62% 0.20% #37 33
Prev: #70
3.2 2,434,866 187.3%
P
S
3,734,866 $22,222,453 2025 Q4 13F Filing 2026-03-31 2026-05-14
ANNX
Annexon Inc
Healthcare 0.61% #38
Prev: #—
3.7 3,958,646
NEW
3,958,646 $21,930,899 2026 Q1 13F Filing 2026-03-31 2026-05-14
TRVI
Trevi Therapeut...
Healthcare 0.59% 0.85% #39 6
Prev: #33
0.2 -500,000 -21.9%
P
S
1,786,867 $21,317,323 2024 Q4 13F Filing 2026-03-31 2026-05-14
RAPP
Rapport Therape...
Healthcare 0.56% 0.64% #40 1
Prev: #39
0.7 -67,000 -9.5%
P
S
641,469 $20,071,565 2024 Q3 13F Filing 2026-03-31 2026-05-14
GOOGL
Alphabet Inc
Communication Services 0.52% 0.19% #41 31
Prev: #72
3.2 45,000 217.4%
P
S
65,703 $18,893,555 2024 Q3 13F Filing 2026-03-31 2026-05-14
FULC
Fulcrum Therape...
Healthcare 0.50% 0.66% #42 4
Prev: #38
2.7 400,000 20.5%
P
S
2,350,000 $18,024,500 2025 Q4 13F Filing 2026-03-31 2026-05-14
WVE
WAVE Life Scien...
Healthcare 0.49% 1.24% #43 15
Prev: #28
1.2 no change no change
P
S
2,450,000 $17,762,500 2024 Q3 13F Filing 2026-03-31 2026-05-14
DFTX
Definium Therap...
Healthcare 0.48% #44
Prev: #—
3.7 919,493
NEW
919,493 $17,378,418 2026 Q1 13F Filing 2026-03-31 2026-05-14
AMLX
Amylyx Pharmace...
Healthcare 0.47% #45
Prev: #—
3.7 1,230,000
NEW
1,230,000 $17,097,000 2026 Q1 13F Filing 2026-03-31 2026-05-14
CGEM
Cullinan Therap...
Healthcare 0.47% 0.37% #46
Prev: #46
1.2 no change no change
P
S
1,193,410 $16,958,356 2024 Q3 13F Filing 2026-03-31 2026-05-14
NMRA
Neumora Therape...
Healthcare 0.46% 0.34% #47 4
Prev: #51
2.7 2,209,039 35.1%
P
S
8,497,822 $16,570,753 2024 Q3 13F Filing 2026-03-31 2026-05-14
QURE
Uniqure NV
Healthcare 0.45% #48
Prev: #—
3.7 1,000,000
NEW
1,000,000 $16,350,000 2025 Q3 13F Filing 2026-03-31 2026-05-14
CTMX
CytomX Therapeu...
Healthcare 0.45% #49
Prev: #—
3.7 3,457,711
NEW
3,457,711 $16,251,242 2026 Q1 13F Filing 2026-03-31 2026-05-14
NVDA
NVIDIA Corp
Technology 0.43% 0.21% #50 15
Prev: #65
3.2 51,600 137.7%
P
S
89,085 $15,536,424 2024 Q3 13F Filing 2026-03-31 2026-05-14
Showing 1-50 of 132 holdings

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