Siren, L.L.C.

All Holdings — 2025 Q4

AI Portfolio Summary
In 2025 Q4, Siren, L.L.C. maintained a portfolio of 141 distinct positions. The most significant new addition to the portfolio was Olema Pharmaceutical, which now represents 2.46% of the total fund value. They heavily accumulated shares in Scholar Rock Holding, increasing their position by 17.0%. The fund also reduced its exposure to Arrowhead Pharmaceut by 43.8%.
PCA Score Concentration Risk
Risk ENB
Total Positions
141
Quarter
2025 Q4
Top Holding
SRRK (14.2%)
Top 10 Concentration
46.3%
Turnover Rate
23.4%
Sector HHI
0.18
Items per page:
Showing 1-50 of 141
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 14.22% 13.48% #1
Prev: #1
8.0 1,575,008 17.0%
P
S
10,825,013 $476,841,823 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
KYMR
Kymera Therapeu...
Healthcare 7.63% 7.59% #2
Prev: #2
5.1 -141,320 -4.1%
P
S
3,286,830 $255,748,242 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
ONC
BeOne Medicines...
Healthcare 4.53% 6.57% #3
Prev: #3
3.3 7,010 1.4%
P
S
500,000 $151,905,000 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
EWTX
Edgewise Therap...
Healthcare 3.35% 2.47% #4 4
Prev: #8
3.8 632,891 16.2%
P
S
4,529,990 $112,411,702 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
RVMD
Revolution Medi...
Healthcare 3.17% 1.91% #5 12
Prev: #17
4.3 291,355 27.9%
P
S
1,335,075 $106,338,724 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
CNTA
Centessa Pharma...
Healthcare 3.00% 3.06% #6
Prev: #6
3.7 800,000 24.8%
P
S
4,027,517 $100,728,200 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
ARWR
Arrowhead Pharm...
Healthcare 2.97% 3.60% #7 3
Prev: #4
1.2 -1,169,404 -43.8%
P
S
1,500,476 $99,616,602 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
BCAX
Bicara Therapeu...
Healthcare 2.62% 3.22% #8 3
Prev: #5
2.0 no change no change
P
S
5,216,969 $87,801,588 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
OLMA
Olema Pharmaceu...
Healthcare 2.46% #9
Prev: #—
4.5 3,300,700 no change
NEW
3,300,700 $82,517,500 2025 Q4 13F Filing 2025-12-31 2026-02-14 (Est.)
IRON
Disc Medicine I...
Healthcare 2.34% 2.36% #10 1
Prev: #9
2.9 75,000 8.2%
P
S
988,401 $78,488,923 2025 Q1 13F Filing 2025-12-31 2026-02-14 (Est.)
GPCR
Structure Thera...
Healthcare 2.24% 1.12% #11 17
Prev: #28
2.9 51,887 5.1%
P
S
1,078,698 $75,023,446 2025 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
TNGX
Tango Therapeut...
Healthcare 2.16% 1.93% #12 4
Prev: #16
3.4 2,282,186 38.8%
P
S
8,165,374 $72,345,214 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
RCUS
Arcus Bioscienc...
Healthcare 2.14% 1.55% #13 9
Prev: #22
1.4 95,000 3.3%
P
S
3,007,077 $71,658,645 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
STOK
Stoke Therapeut...
Healthcare 2.13% 2.07% #14 1
Prev: #13
1.9 no change no change
P
S
2,247,347 $71,330,794 2024 Q4 13F Filing 2025-12-31 2026-02-14 (Est.)
CRNX
Crinetics Pharm...
Healthcare 2.09% 2.75% #15 8
Prev: #7
1.3 -180,975 -10.7%
P
S
1,507,636 $70,180,456 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
DYN
Dyne Therapeuti...
Healthcare 2.04% 2.34% #16 6
Prev: #10
0.8 -1,226,233 -25.9%
P
S
3,502,941 $68,517,526 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
APLS
Apellis Pharmac...
Healthcare 1.93% 2.28% #17 6
Prev: #11
1.8 no change no change
P
S
2,578,396 $64,769,308 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
COGT
Cogent Bioscien...
Healthcare 1.73% 0.97% #18 13
Prev: #31
1.2 -95,000 -5.5%
P
S
1,629,279 $57,871,990 2025 Q2 13F Filing 2025-12-31 2026-02-14 (Est.)
SEPN
Septerna Inc
Healthcare 1.66% 1.62% #19 2
Prev: #21
1.2 -202,514 -9.2%
P
S
2,000,000 $55,760,000 2024 Q4 13F Filing 2025-12-31 2026-02-14 (Est.)
TSHA
Taysha Gene The...
Healthcare 1.66% 1.41% #20 3
Prev: #23
1.2 -884,824 -8.0%
P
S
10,129,913 $55,714,522 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
RYTM
Rhythm Pharmace...
Healthcare 1.60% 1.98% #21 6
Prev: #15
1.6 no change no change
P
S
499,975 $53,517,324 2025 Q1 13F Filing 2025-12-31 2026-02-14 (Est.)
ASND
Ascendis Pharma...
Healthcare 1.50% 1.83% #22 4
Prev: #18
1.6 no change no change
P
S
235,862 $50,295,213 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
RAPT
RAPT Therapeuti...
Healthcare 1.39% 0.59% #23 17
Prev: #40
3.6 794,534 136.9%
P
S
1,375,000 $46,571,250 2025 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
TBLA
Taboola.com Ltd
Communication Services 1.37% 1.33% #24
Prev: #24
1.5 no change no change
P
S
9,969,495 $45,959,372 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
LXRX
Lexicon Pharmac...
Healthcare 1.34% 2.06% #25 11
Prev: #14
1.5 no change no change
P
S
38,918,903 $44,756,738 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
ZYME
Zymeworks Inc
Healthcare 1.32% #26
Prev: #—
4.0 1,680,121 no change
NEW
1,680,121 $44,237,586 2025 Q4 13F Filing 2025-12-31 2026-02-14 (Est.)
SLDB
Solid Bioscienc...
Healthcare 1.29% 1.79% #27 7
Prev: #20
1.0 274,500 3.7%
P
S
7,690,405 $43,373,884 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
WVE
WAVE Life Scien...
Healthcare 1.24% 1.06% #28 1
Prev: #29
0.5 -1,246,322 -33.7%
P
S
2,450,000 $41,650,000 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
XENE
Xenon Pharmaceu...
Healthcare 1.09% 1.28% #29 4
Prev: #25
1.4 no change no change
P
S
812,761 $36,427,948 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
DBVT
Dbv Technologie...
Healthcare 1.06% #30
Prev: #—
3.9 1,857,362 no change
NEW
1,857,362 $35,605,630 2025 Q4 13F Filing 2025-12-31 2026-02-14 (Est.)
ERAS
Erasca Inc
Healthcare 0.97% 0.75% #31 4
Prev: #35
1.4 no change no change
P
S
8,757,249 $32,576,966 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
ENGN
enGene Holdings...
Healthcare 0.90% #32
Prev: #—
3.9 3,336,264 no change
NEW
3,336,264 $30,126,464 2025 Q4 13F Filing 2025-12-31 2026-02-14 (Est.)
TRVI
Trevi Therapeut...
Healthcare 0.85% 0.91% #33 1
Prev: #32
0.8 -250,000 -9.9%
P
S
2,286,867 $28,631,575 2024 Q4 13F Filing 2025-12-31 2026-02-14 (Est.)
SYRE
Spyre Therapeut...
Healthcare 0.80% 0.24% #34 25
Prev: #59
3.3 450,000 122.1%
P
S
818,598 $26,817,270 2024 Q4 13F Filing 2025-12-31 2026-02-14 (Est.)
MLYS
Mineralys Thera...
Healthcare 0.76% #35
Prev: #—
3.8 699,999 no change
NEW
699,999 $25,402,964 2025 Q4 13F Filing 2025-12-31 2026-02-14 (Est.)
DNLI
Denali Therapeu...
Healthcare 0.69% 0.47% #36 10
Prev: #46
3.3 575,000 70.0%
P
S
1,396,513 $23,056,430 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
RELY
Remitly Global ...
Technology 0.67% 1.03% #37 7
Prev: #30
1.3 no change no change
P
S
1,618,271 $22,332,140 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
FULC
Fulcrum Therape...
Healthcare 0.66% #38
Prev: #—
3.8 1,950,000 no change
NEW
1,950,000 $22,054,500 2025 Q4 13F Filing 2025-12-31 2026-02-14 (Est.)
RAPP
Rapport Therape...
Healthcare 0.64% 1.22% #39 12
Prev: #27
0.3 -345,000 -32.7%
P
S
708,469 $21,494,949 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
SLN
Silence Therape...
Healthcare 0.53% 0.59% #40 1
Prev: #39
1.2 no change no change
P
S
2,911,438 $17,701,543 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
IHS
IHS Holding Lim...
Real Estate 0.52% 0.63% #41 5
Prev: #36
1.2 no change no change
P
S
2,357,520 $17,587,099 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
GOSS
Gossamer Bio In...
Healthcare 0.48% 0.54% #42
Prev: #42
1.2 no change no change
P
S
5,208,968 $16,147,801 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
UPB
Upstream Bio In...
Healthcare 0.48% 0.58% #43 2
Prev: #41
0.2 -200,000 -25.4%
P
S
588,450 $15,976,418 2024 Q4 13F Filing 2025-12-31 2026-02-14 (Est.)
BCYC
Bicycle Therape...
Healthcare 0.43% 0.61% #44 6
Prev: #38
1.2 no change no change
P
S
2,012,752 $14,250,284 2024 Q4 13F Filing 2025-12-31 2026-02-14 (Est.)
MNPR
Monopar Therape...
Healthcare 0.41% #45
Prev: #—
3.7 212,298 no change
NEW
212,298 $13,863,059 2025 Q4 13F Filing 2025-12-31 2026-02-14 (Est.)
CGEM
Cullinan Therap...
Healthcare 0.37% 0.28% #46 10
Prev: #56
1.1 no change no change
P
S
1,193,410 $12,351,794 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
SION
Sionna Therapeu...
Healthcare 0.37% 0.37% #47 1
Prev: #48
0.6 -25,000 -7.7%
P
S
300,000 $12,342,000 2025 Q1 13F Filing 2025-12-31 2026-02-14 (Est.)
IKT
Inhibikase Ther...
Healthcare 0.36% #48
Prev: #—
3.6 5,850,000 no change
NEW
5,850,000 $11,992,500 2025 Q4 13F Filing 2025-12-31 2026-02-14 (Est.)
IMAB
NovaBridge Bios...
Unknown 0.36% 0.17% #49 20
Prev: #69
3.1 1,834,043 157.3%
P
S
3,000,000 $11,940,000 2025 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
AMZN
Amazon.com Inc
Consumer Cyclical 0.35% 0.50% #50 6
Prev: #44
0.6 -7,000 -12.0%
P
S
51,500 $11,887,230 2024 Q3 13F Filing 2025-12-31 2026-02-14 (Est.)
Showing 1-50 of 141 holdings

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