Castle Biosciences, Inc.
US ˙ NasdaqGM ˙ US14843C1053

SecurityCSTL / Castle Biosciences, Inc.
InstitutionState Street Corp
Latest Disclosed Ownership769,079 shares
Latest Disclosed Value $ 18,880,889
State Street Corp reports 4.43% increase in ownership of CSTL / Castle Biosciences, Inc.

On May 15, 2026 - State Street Corp filed a 13F-HR form disclosing ownership of 769,079 shares of Castle Biosciences, Inc. (US:CSTL) valued at $18,880,889 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 736,454 shares of Castle Biosciences, Inc.. This represents a change in shares of 4.43% during the quarter. The current value of the position is $16,612,106 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-15 2026-03-31 13F CASTLE BIOSCIENCES COM 14843C105 769,079 32,625 4.43 18,881 -34.10 0.0007
2026-02-13 2025-12-31 13F CASTLE BIOSCIENCES COM 14843C105 736,454 12,374 1.71 28,648 73.76 0.0010
2025-11-14 2025-09-30 13F CASTLE BIOSCIENCES COM 14843C105 724,080 16,393 2.32 16,487 14.10 0.0006
2025-08-14 2025-06-30 13F CASTLE BIOSCIENCES COM 14843C105 707,687 -7,341 -1.03 14,451 0.95 0.0005
2025-05-15 2025-03-31 13F CASTLE BIOSCIENCES COM 14843C105 715,028 4,816 0.68 14,315 -24.37 0.0006
2025-02-14 2024-12-31 13F CASTLE BIOSCIENCES COM 14843C105 710,212 30,211 4.44 18,927 -2.40 0.0007
2024-11-14 2024-09-30 13F CASTLE BIOSCIENCES COM 14843C105 680,001 60,924 9.84 19,394 43.90 0.0008
2024-08-14 2024-06-30 13F CASTLE BIOSCIENCES COM 14843C105 619,077 13,278 2.19 13,477 0.44 0.0006
2024-05-15 2024-03-31 13F CASTLE BIOSCIENCES COM 14843C105 605,799 25,881 4.46 13,418 7.22 0.0006
2024-02-14 2023-12-31 13F CASTLE BIOSCIENCES COM 14843C105 579,918 14,754 2.61 12,515 31.11 0.0006
2023-11-14 2023-09-30 13F CASTLE BIOSCIENCES COM 14843C105 565,164 29,836 5.57 9,546 29.97 0.0005
2023-08-14 2023-06-30 13F CASTLE BIOSCIENCES COM 14843C105 535,328 12,800 2.45 7,345 -38.13 0.0004
2023-05-15 2023-03-31 13F CASTLE BIOSCIENCES COM 14843C105 522,528 18,075 3.58 11,872 -0.03 0.0007
2023-05-15 2022-12-31 13F/A-99 CASTLE BIOSCIENCES COM 14843C105 504,453 6,528 1.31 11,875 -8.56 0.0007
2023-05-15 2022-12-31 13F CASTLE BIOSCIENCES COM 14843C105 504,453 6,528 11,875 0.0007
2022-11-15 2022-09-30 13F CASTLE BIOSCIENCES COM 14843C105 497,925 -6,599 -1.31 12,986 17.27 0.0008
2022-08-15 2022-06-30 13F CASTLE BIOSCIENCES COM 14843C105 504,524 45,819 9.99 11,074 -46.19 0.0007
2022-05-16 2022-03-31 13F CASTLE BIOSCIENCES COM 14843C105 458,705 2,666 0.58 20,578 5.26 0.0010
2022-02-14 2021-12-31 13F CASTLE BIOSCIENCES COM 14843C105 456,039 21,202 4.88 19,550 -32.39 0.0009
2021-11-15 2021-09-30 13F CASTLE BIOSCIENCES COM 14843C105 434,837 3,939 0.91 28,917 -8.48 0.0015
2021-08-16 2021-06-30 13F CASTLE BIOSCIENCES COM 14843C105 430,898 125,419 41.06 31,598 51.09 0.0017
2021-07-09 2021-03-31 13F/A-1 CASTLE BIOSCIENCES COM 14843C105 305,479 44,056 16.85 20,913 19.13 0.0012
2021-05-17 2021-03-31 13F CASTLE BIOSCIENCES COM 14843C105 305,479 44,056 20,913 0.0012
2021-02-16 2020-12-31 13F CASTLE BIOSCIENCES COM 14843C105 261,423 53,303 25.61 17,555 63.94 0.0011
2020-11-10 2020-09-30 13F CASTLE BIOSCIENCES COM 14843C105 208,120 21,262 11.38 10,708 52.04 0.0007
2020-08-14 2020-06-30 13F CASTLE BIOSCIENCES COM 14843C105 186,858 36,879 24.59 7,043 57.53 0.0005
2020-06-19 2020-03-31 13F/A-1 CASTLE BIOSCIENCES COM 14843C105 149,979 98,866 193.43 4,471 154.47 0.0004
2020-05-11 2020-03-31 13F CASTLE BIOSCIENCES COM 14843C105 149,979 98,866 4,471 392.6438
2020-02-06 2019-12-31 13F CASTLE BIOSCIENCES COM 14843C105 51,113 15,091 41.89 1,757 169.48 0.0001
2019-11-14 2019-09-30 13F CASTLE BIOSCIENCES COM 14843C105 36,022 36,022 652 0.0000
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.