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Equibles

Portolan Capital Management, LLC

Position in CSTL — Castle Biosciences Inc

CIK 1350290 BOSTON, MA
Back to CSTL Full portfolio

Position in CSTL

as of Jun 30, 2026 · filed Aug 14, 2026
Position Value
$7,842,309
-$25,307,138 QoQ
Shares Held
328,818
-75.6% QoQ
Ownership
1.08%
of shares outstanding
% of Portfolio
0.30%
of 13F equity value
Holder Rank
#22
of 176 holders
Holding Since
Mar 2020
22 quarters on record
Voting authority Sole 100% Shared 0% None 0%

Common Shares in CSTL Over Time

Shares Held

Position Value (USD)

Position in Diagnostics & Research

Healthcare · as of Jun 30, 2026

Portolan Capital Management, LLC holds $45,511,852 across 5 Diagnostics & Research names. CSTL ranks #3 (17.2% of the industry book) .

# Ticker Company Shares Value (USD) Open
1 CDNA
CareDx, Inc.
 684,805 $19,516,942
2 WGS
GeneDx Holdings Corp.
 200,315 $13,751,624
3 CSTL
Castle Biosciences Inc
This page 		328,818 $7,842,309
4 NTRA
Natera, Inc.
 8,532 $2,316,011
5 GH
Guardant Health, Inc.
 13,897 $2,084,966

All Filings in CSTL

Export CSV
22 filing rows on record
Report Date Value (USD) Shares
2026-06-30 $7,842,309 328,818
2026-03-31 $33,149,447 1,350,283
2025-12-31 $67,276,110 1,729,463
2025-09-30 $34,499,077 1,515,111
2025-06-30 $30,417,060 1,489,572
2025-03-31 $25,329,764 1,265,223
2024-12-31 $20,695,830 776,579
2024-09-30 $35,810,510 1,255,628
2024-06-30 $26,362,425 1,210,952
2024-03-31 $23,111,531 1,043,410
2023-12-31 $15,724,331 728,653
2023-09-30 $4,273,642 253,028
2023-06-30 $5,919,823 431,474
2023-03-31 $5,831,065 256,649
2022-12-31 $13,740,674 583,716
2022-09-30 $7,839,387 300,590
2022-06-30 $3,401,547 154,968
2021-06-30 $669,282 9,127
2020-12-31 $1,112,876 16,573
2020-09-30 $1,421,666 27,632
2020-06-30 $2,707,423 71,834
2020-03-31 $4,043,845 135,654