Position in CSTL
as of Mar 31, 2026
· filed May 15, 2026
Position Value
$33,149,447
-$34,126,663 QoQ
Shares Held
1,350,283
-21.9% QoQ
Ownership
4.45%
of shares outstanding
% of Portfolio
1.78%
of 13F equity value
Holder Rank
—
not a current holder
Holding Since
Mar 2020
21 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 Mar 31, 2026Portolan Capital Management, LLC holds $56,950,930 across 8 Diagnostics & Research names. CSTL ranks #1 (58.2% of the industry book) .
| # | Ticker | Company | Shares | Value (USD) | Open |
|---|---|---|---|---|---|
| 1 | CSTL |
Castle Biosciences Inc
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|
1,350,283 | $33,149,447 | |
| 2 | WGS |
GeneDx Holdings Corp.
|
102,575 | $6,587,366 | |
| 3 | CDNA |
CareDx, Inc.
|
340,352 | $5,908,510 | |
| 4 | PSNL |
Personalis, Inc.
|
736,713 | $4,692,861 | |
| 5 | NTRA |
Natera, Inc.
|
11,418 | $2,283,485 | |
| 6 | FLGT |
Fulgent Genetics, Inc.
|
106,642 | $1,695,607 | |
| 7 | RDNT |
RadNet, Inc.
|
23,728 | $1,326,157 | |
| 8 | GH |
Guardant Health, Inc.
|
14,155 | $1,307,497 |
All Filings in CSTL
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23 filing rows on record
| Report Date | Value (USD) | Shares | Type | Discretion | Filed | |
|---|---|---|---|---|---|---|
| 2026-03-31 | $33,149,447 | 1,350,283 | Shares | Sole | 2026-05-15 | |
| 2026-03-31 | $33,149,447 | 1,350,283 | Shares | Sole | 2026-05-15 | |
| 2025-12-31 | $67,276,110 | 1,729,463 | Shares | Sole | 2026-02-17 | |
| 2025-09-30 | $34,499,077 | 1,515,111 | Shares | Sole | 2025-11-13 | |
| 2025-06-30 | $30,417,060 | 1,489,572 | Shares | Sole | 2025-08-13 | |
| 2025-04-07 | $30,755,879 | 1,611,099 | Shares | Sole | 2025-04-14 | |
| 2025-03-31 | $25,329,764 | 1,265,223 | Shares | Sole | 2025-05-15 | |
| 2024-12-31 | $20,695,830 | 776,579 | Shares | Sole | 2025-02-13 | |
| 2024-09-30 | $35,810,510 | 1,255,628 | Shares | Sole | 2024-11-14 | |
| 2024-06-30 | $26,362,425 | 1,210,952 | Shares | Sole | 2024-08-14 | |
| 2024-03-31 | $23,111,531 | 1,043,410 | Shares | Sole | 2024-05-15 | |
| 2023-12-31 | $15,724,331 | 728,653 | Shares | Sole | 2024-02-14 | |
| 2023-09-30 | $4,273,642 | 253,028 | Shares | Sole | 2023-11-14 | |
| 2023-06-30 | $5,919,823 | 431,474 | Shares | Sole | 2023-08-14 | |
| 2023-03-31 | $5,831,065 | 256,649 | Shares | Sole | 2023-05-15 | |
| 2022-12-31 | $13,740,674 | 583,716 | Shares | Sole | 2023-02-13 | |
| 2022-09-30 | $7,839,387 | 300,590 | Shares | Sole | 2022-11-14 | |
| 2022-06-30 | $3,401,547 | 154,968 | Shares | Sole | 2022-08-15 | |
| 2021-06-30 | $669,282 | 9,127 | Shares | Sole | 2021-08-16 | |
| 2020-12-31 | $1,112,876 | 16,573 | Shares | Sole | 2021-02-16 | |
| 2020-09-30 | $1,421,666 | 27,632 | Shares | Sole | 2020-11-16 | |
| 2020-06-30 | $2,707,423 | 71,834 | Shares | Sole | 2020-08-14 | |
| 2020-03-31 | $4,043,845 | 135,654 | Shares | Sole | 2020-05-14 | |
| No filing history on record for this holder in this stock. | ||||||