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Livermore
Livermore
ZHEN

Siren, L.L.C.

SEC CIK
0002005245
Latest filing
Aug 13, 2026

The latest 13F from Siren, L.L.C. covers Q2 2026 (filed Aug 13, 2026): 115 long positions worth $4.93B. The top 10 holdings make up 44.8% of the portfolio, and the largest is Scholar Rock Holding Corp (SRRK) at 10.7%. Livermore has 9 filings on Form 13F from this institution, going back to Q3 2024.

What changed in Q2 2026

Share counts compared with Q1 2026: how many positions were new, added to, reduced or sold out, and the biggest buys and sells. Dollar amounts are estimated at the quarter-end prices implied by the filing.

Full comparison
New
24
Est. +$516.7M
Added
32
Est. +$282.7M
Reduced
21
Est. −$325.2M
Sold out
9
Est. −$108.8M

Top 5 holdings

Share of this quarter's portfolio value

  1. SRRKScholar Rock Holding Corp
    10.7%$526.6MHistory
  2. KYMRKymera Therapeutics, Inc.
    6.8%$336.7MHistory
  3. ERASErasca, Inc.
    4.2%$208.8MHistory
  4. MANEVeradermics, Inc
    4.1%$203.5MHistory
  5. TNGXTango Therapeutics, Inc.
    3.9%$193.2MHistory

Biggest buys

New and added positions, by estimated amount bought

  1. PBLSParabilis Medicines, Inc.
    +$81.9MNewHistory
  2. ABVXAbivax S.A.
    +$76.8MNewHistory
  3. COAGHemab Therapeutics Holdings, Inc.
    +$76.6MNewHistory
  4. RLAYRelay Therapeutics, Inc.
    +$68.3MNewHistory
  5. ELVNEnliven Therapeutics, Inc.
    +$52.2MAddedHistory

Largest weight increases

New and added positions, by percentage points of the portfolio gained

  1. PBLSParabilis Medicines, Inc.
    +1.66 pp0.0% → 1.7%History
  2. ABVXAbivax S.A.
    +1.56 pp0.0% → 1.6%History
  3. COAGHemab Therapeutics Holdings, Inc.
    +1.56 pp0.0% → 1.6%History
  4. MANEVeradermics, Inc
    +1.50 pp2.6% → 4.1%History
  5. RLAYRelay Therapeutics, Inc.
    +1.39 pp0.0% → 1.4%History

Biggest sells

Reduced and sold-out positions, by estimated amount sold

  1. SRRKScholar Rock Holding Corp
    −$68.8MReducedHistory
  2. EWTXEdgewise Therapeutics, Inc.
    −$50.6MReducedHistory
  3. CNTACentessa Pharmaceuticals plc
    −$41.8MSold outHistory
  4. RVMDRevolution Medicines, Inc.
    −$39.5MReducedHistory
  5. KYMRKymera Therapeutics, Inc.
    −$28.8MReducedHistory

Largest weight decreases

Reduced and sold-out positions, by percentage points of the portfolio lost

  1. SRRKScholar Rock Holding Corp
    −4.06 pp14.8% → 10.7%History
  2. EWTXEdgewise Therapeutics, Inc.
    −1.24 pp3.9% → 2.6%History
  3. CNTACentessa Pharmaceuticals plc
    −1.16 pp1.2% → 0.0%History
  4. CRNXCrinetics Pharmaceuticals, Inc.
    −0.84 pp1.9% → 1.1%History
  5. GPCRStructure Therapeutics Inc.
    −0.82 pp1.8% → 1.0%History

Metrics

13F metrics for Q2 2026, computed only from the numbers in the filings. Definitions below.

Portfolio value
$4.93B
+$1.32B (+36.5%) vs. prior quarter
Positions
115
+15 vs. prior quarter
Top 10 concentration
44.8%
Top 10 as share of value
Turnover
10.2%
Q2 2026, one quarter
Average holding period
6.0 quarters
Weighted by value

How these are calculated

  • Portfolio value: the market value of all long positions in the 13F, as reported at quarter end, excluding options.
  • Top 10 concentration: the combined value of the 10 largest positions as a share of portfolio value.
  • Turnover: the smaller of this quarter's estimated purchases and estimated sales, divided by the average of this and last quarter's portfolio value. Estimates multiply the change in shares by the quarter-end price implied by the filing (market value divided by shares); new positions use this quarter's value and sold-out positions last quarter's. Only positions reported in shares count, and it is not calculated when the previous quarter was not filed.
  • Average holding period: how many consecutive quarters each current position has been held (including this one; a quarter without the position or without a filing starts the count over), weighted by this quarter's value. Counting starts with the first 13F in Livermore (Q3 2024), so positions held before then are understated.

13F filings by quarter

8 quarters, going back to Q3 2024. Bars show each quarter's 13F portfolio value; quarters without a filing are left blank.

Peak $4.93B (Q2 2026)

Q3 2024: $2.00BQ4 2024: $2.26BQ1 2025: $1.77BQ2 2025: $1.93BQ3 2025: $2.56BQ4 2025: $3.35BQ1 2026: $3.61BQ2 2026: $4.93B
Q3 2024Q2 2026
13F filings of Siren, L.L.C. by quarter
QuarterFiledPositionsValueTop 3 holdingsChangesFiling
Q2 2026Aug 13, 2026115$4.93BSRRKKYMRERASvs. Q1 2026SEC
Q1 2026May 14, 2026100$3.61BSRRKKYMRERASvs. Q4 2025SEC
Q4 2025Feb 13, 2026113$3.35BSRRKKYMRONCvs. Q3 2025SEC
Q3 2025Nov 13, 2025115$2.56BSRRKKYMRONCvs. Q2 2025SEC
Q2 2025Aug 13, 2025110$1.93BSRRKKYMRONCvs. Q1 2025SEC
Q1 2025May 23, 2025Amended116$1.77BSRRKONCKYMRvs. Q4 2024SEC
Q4 2024Feb 14, 2025117$2.26BSRRKONCKYMRvs. Q3 2024SEC
Q3 2024Nov 13, 2024109$2.00BKYMRONCSRRK–SEC

13D and 13G filings

Companies where Siren, L.L.C. reports owning 5% or more on Schedule 13D or 13G, and its latest filings.

Current stakes of 5% or more

Siren, L.L.C. does not currently report owning 5% or more of any company.

Latest filings

27 filings on file made by Siren, L.L.C. or listing it as a reporting person; the latest 20 are shown.

Schedule 13D and 13G filings by Siren, L.L.C.
CompanyFiled (ET)FilerFormStakeChangeEvent dateFiling
OLMAOlema Pharmaceuticals, Inc.Mar 20, 202610:37 AM ETInvus Global Management, LLCand 7 others13G5.10%4.46M sharesNewMar 16, 2026SEC
BCYCBicycle Therapeutics PLCMar 3, 20265:39 PM ETInvus Global Management, LLCand 7 others13G6.30%3.15M sharesNewFeb 25, 2026SEC
NMRANeumora Therapeutics, Inc.Feb 19, 20264:37 PM ETInvus Global Management, LLCand 7 others13G5.40%9.00M sharesNewFeb 13, 2026SEC
TNGXTango Therapeutics, Inc.Feb 13, 202611:47 AM ETInvus Global Management, LLCand 7 others13G/A6.10%8.17M shares+0.80 ppfrom 5.30%Dec 31, 2025SEC
RZLTRezolute, Inc.Feb 13, 202611:40 AM ETInvus Global Management, LLCand 7 others13G/A0.00%0 shares−5.40 ppfrom 5.40%Below 5%Dec 31, 2025SEC
DBVTDBV Technologies S.A.Feb 13, 202611:25 AM ETInvus Global Management, LLCand 7 others13G/A6.20%14.4M shares−1.60 ppfrom 7.80%Dec 31, 2025SEC
ABVXAbivax S.A.Feb 13, 202611:14 AM ETInvus Global Management, LLCand 4 others13G/A5.00%3.92M shares−3.50 ppfrom 8.50%Dec 31, 2025SEC
ENGNenGene Therapeutics Inc.Jan 27, 20262:18 PM ETInvus Global Management, LLCand 7 others13G6.30%4.24M sharesNewJan 21, 2026SEC
VTVTvTv Therapeutics Inc.Nov 12, 202510:29 AM ETInvus Global Management, LLCand 7 others13G/A9.40%393.1K shares−0.59 ppfrom 9.99%Sep 30, 2025SEC
RANIRani Therapeutics Holdings, Inc.Oct 23, 20255:05 PM ETInvus Global Management, LLCand 7 others13G9.99%9.83M sharesNewOct 16, 2025SEC
DBVTDBV Technologies S.A.Oct 14, 20255:14 PM ETInvus Global Management, LLCand 7 others13G7.80%11.5M sharesNewOct 6, 2025SEC
TENXTenax Therapeutics, Inc.Oct 2, 20255:04 PM ETInvus Global Management, LLCand 7 others13G9.40%427.1K sharesNewSep 26, 2025SEC
TNGXTango Therapeutics, Inc.Sep 22, 20255:22 PM ETInvus Global Management, LLCand 7 others13G5.30%5.88M sharesNewSep 19, 2025SEC
RZLTRezolute, Inc.Sep 22, 20253:15 PM ETInvus Global Management, LLCand 7 others13G5.40%4.87M sharesNewSep 18, 2025SEC
VTVTvTv Therapeutics Inc.Sep 8, 20255:43 PM ETInvus Global Management, LLCand 7 others13G9.99%348.1K sharesNewAug 29, 2025SEC
BCAXBicara Therapeutics Inc.Jul 31, 20252:56 PM ETInvus Global Management, LLCand 7 others13G/A9.60%5.22M shares–Jun 30, 2025SEC
IVAInventiva S.A.Jul 31, 20252:48 PM ETInvus Global Management, LLCand 4 others13G/A10.60%14.8M shares+2.80 ppfrom 7.80%Jun 30, 2025SEC
KLRSKalaris Therapeutics, Inc.Jul 29, 20251:21 PM ETInvus Global Management, LLCand 4 others13G/A1.50%282.6K shares–Below 5%Jun 30, 2025SEC
SLDBSolid Biosciences Inc.Apr 17, 20256:50 PM ETInvus Global Management, LLCand 7 others13G/A9.60%7.42M shares+0.20 ppfrom 9.40%Mar 31, 2025SEC
NBTXNanobiotix S.A.Apr 17, 20254:30 PM ETInvus Global Management, LLCand 4 others13G8.90%4.23M sharesNewDec 31, 2023SEC