캐슬 바이오사이언시스, Inc.
US ˙ NasdaqGM ˙ US14843C1053

SecurityCSTL / Castle Biosciences, Inc.
InstitutionMorgan Stanley
Latest Disclosed Ownership428,934 shares
Latest Disclosed Value $ 10,530,333
Morgan Stanley reports 110.70% increase in ownership of CSTL / Castle Biosciences, Inc.

On May 15, 2026 - Morgan Stanley filed a 13F-HR form disclosing ownership of 428,934 shares of Castle Biosciences, Inc. (US:CSTL) valued at $10,530,330 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on May 27, 2026 disclosing 203,577 shares of Castle Biosciences, Inc.. This represents a change in shares of 110.70% during the quarter. The current value of the position is $9,011,903 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 428,934 225,357 110.70 10,530 32.97 0.0006
2026-05-27 2025-12-31 13F/A-1 CASTLE BIOSCIENCES COM 14843C105 203,577 -66,054 -24.50 7,919 28.99 0.0005
2026-02-13 2025-12-31 13F CASTLE BIOSCIENCES COM 14843C105 203,577 -66,054 7,919 0.0005
2026-05-27 2025-09-30 13F/A-1 CASTLE BIOSCIENCES COM 14843C105 269,631 102,043 60.89 6,140 79.40 0.0004
2025-11-14 2025-09-30 13F CASTLE BIOSCIENCES COM 14843C105 269,631 102,043 6,140 0.0004
2025-08-15 2025-06-30 13F CASTLE BIOSCIENCES COM 14843C105 167,588 -44,205 -20.87 3,422 -19.29 0.0002
2025-05-15 2025-03-31 13F CASTLE BIOSCIENCES COM 14843C105 211,793 -94,884 -30.94 4,240 -48.12 0.0003
2025-05-15 2024-12-31 13F/A-1 CASTLE BIOSCIENCES COM 14843C105 306,677 -90,242 -22.74 8,173 -27.81 0.0006
2025-02-14 2024-12-31 13F CASTLE BIOSCIENCES COM 14843C105 306,677 -90,242 8,173 0.0006
2025-05-14 2024-09-30 13F/A-2 CASTLE BIOSCIENCES COM 14843C105 396,919 147,539 59.16 11,320 108.51 0.0008
2025-02-14 2024-09-30 13F/A-1 CASTLE BIOSCIENCES COM 14843C105 396,919 147,539 11,320 0.0008
2024-11-14 2024-09-30 13F CASTLE BIOSCIENCES COM 14843C105 396,919 147,539 11,320 0.0001
2025-05-14 2024-06-30 13F/A-2 CASTLE BIOSCIENCES COM 14843C105 249,380 -401,331 -61.68 5,429 -62.33 0.0004
2024-10-17 2024-06-30 13F/A-1 CASTLE BIOSCIENCES COM 14843C105 249,380 -401,331 5,429 0.0004
2024-08-14 2024-06-30 13F CASTLE BIOSCIENCES COM 14843C105 249,380 -401,331 5,429 0.0004
2024-10-17 2024-03-31 13F/A-2 CASTLE BIOSCIENCES COM 14843C105 650,711 172,676 36.12 14,413 39.73 0.0012
2024-08-16 2024-03-31 13F/A-1 CASTLE BIOSCIENCES COM 14843C105 650,711 172,676 14,413 0.0001
2024-05-15 2024-03-31 13F CASTLE BIOSCIENCES COM 14843C105 650,711 172,676 14,413 0.0012
2024-08-16 2023-12-31 13F/A-1 CASTLE BIOSCIENCES COM 14843C105 478,035 439,389 1,136.96 10,316 1,482.06 0.0009
2024-02-13 2023-12-31 13F CASTLE BIOSCIENCES COM 14843C105 478,035 439,389 10,316 0.0009
2023-11-15 2023-09-30 13F CASTLE BIOSCIENCES COM 14843C105 38,646 -66,134 -63.12 653 -54.63 0.0001
2023-08-14 2023-06-30 13F CASTLE BIOSCIENCES COM 14843C105 104,780 15,916 17.91 1,438 -28.79 0.0001
2023-05-15 2023-03-31 13F CASTLE BIOSCIENCES COM 14843C105 88,864 30,546 52.38 2,019 47.08 0.0002
2023-02-14 2022-12-31 13F CASTLE BIOSCIENCES COM 14843C105 58,318 -137,484 -70.22 1,373 -73.13 0.0002
2022-11-14 2022-09-30 13F CASTLE BIOSCIENCES COM 14843C105 195,802 86,863 79.74 5,106 113.64 0.0007
2022-10-27 2022-06-30 13F/A-1 CASTLE BIOSCIENCES COM 14843C105 108,939 81,797 301.37 2,390 96.38 0.0003
2022-08-15 2022-06-30 13F CASTLE BIOSCIENCES COM 14843C105 108,939 81,797 2,390 0.0001
2022-10-27 2022-03-31 13F/A-1 CASTLE BIOSCIENCES COM 14843C105 27,142 -15,757 -36.73 1,217 -33.82 0.0002
2022-05-13 2022-03-31 13F CASTLE BIOSCIENCES COM 14843C105 27,142 -15,757 1,217 0.0002
2022-02-14 2021-12-31 13F CASTLE BIOSCIENCES COM 14843C105 42,899 -26,923 -38.56 1,839 -60.40 0.0002
2021-11-15 2021-09-30 13F CASTLE BIOSCIENCES COM 14843C105 69,822 22,343 47.06 4,644 33.33 0.0006
2021-08-23 2021-06-30 13F/A-1 CASTLE BIOSCIENCES COM 14843C105 47,479 -88,939 -65.20 3,483 -62.70 0.0005
2021-08-16 2021-06-30 13F CASTLE BIOSCIENCES COM 14843C105 47,479 -88,939 3,483 0.0001
2021-05-17 2021-03-31 13F CASTLE BIOSCIENCES COM 14843C105 136,418 60,086 78.72 9,339 82.19 0.0014
2021-02-16 2020-12-31 13F CASTLE BIOSCIENCES COM 14843C105 76,332 23,052 43.27 5,126 86.94 0.0008
2020-11-13 2020-09-30 13F CASTLE BIOSCIENCES COM 14843C105 53,280 -262,236 -83.11 2,742 -76.94 0.0005
2020-08-14 2020-06-30 13F CASTLE BIOSCIENCES COM 14843C105 315,516 314,133 22,713.88 11,891 28,902.44 0.0026
2020-05-26 2020-03-31 13F/A-1 CASTLE BIOSCIENCES COM 14843C105 1,383 -14,760 -91.43 41 -92.61 0.0000
2020-05-15 2020-03-31 13F CASTLE BIOSCIENCES COM 14843C105 1,383 -14,760 41 3.1497
2020-02-14 2019-12-31 13F CASTLE BIOSCIENCES COM 14843C105 16,143 12,689 367.37 555 780.95 0.0001
2019-11-14 2019-09-30 13F CASTLE BIOSCIENCES COM 14843C105 3,454 3,454 63 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.