CSTL Institutional Ownership & Shareholders
CASTLE BIOSCIENCES INC (CSTL) is currently held by 181 institutional investors tracked by InsiderSet, with a combined reported market value of approximately $686.08M based on the latest available SEC Form 13F filings for the quarter ended June 30, 2026.
Blackrock, Inc. is currently the largest disclosed institutional shareholder of CSTL tracked by InsiderSet, reporting ownership valued at approximately $78.51M in its June 30, 2026 SEC Form 13F filing. Based on current market prices and the latest disclosed share count, the position is now estimated to be worth approximately $107.05M, representing an estimated gain of +36.35% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 53% of the total disclosed CSTL value among the investors covered in this analysis. Major shareholders include Blackrock, Inc., Rtw Investments, Lp, Principal Financial Group Inc, and several other long-term asset managers with concentrated positions in CASTLE BIOSCIENCES INC (CSTL).
This page ranks the largest institutional CSTL shareholders using publicly disclosed SEC Form 13F data, including reported values, estimated current holding values, portfolio allocation percentages, ownership concentration metrics, and historical holding changes across major hedge funds and investment firms.
Institutional Holders
181
Total Reported Value
$686.08M
Largest Holder
Blackrock, Inc.
Largest Position
$78.51M
Insider Transactions (90d)
50
Latest Filing Quarter
Q2 2026
New Institutional Positions
50
Funds Exiting Positions
0
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Blackrock, Inc. | 0.00% | 3,291,963 | $78,513,319 | $107,054,637 | +$28,541,318 | +36.35% | |
| Rtw Investments, Lp | 0.57% | 2,778,335 | $66,263,290 | $90,351,454 | +$24,088,164 | +36.35% | |
| Principal Financial Group Inc | 0.03% | 1,500,897 | $53,326,870 | $48,809,170 | -$4,517,700 | -8.47% | |
| Vanguard Capital Management Llc | 0.00% | 1,226,497 | $29,251,953 | $39,885,682 | +$10,633,729 | +36.35% | |
| Geode Capital Management, Llc | 0.00% | 793,904 | $28,213,299 | $25,817,758 | -$2,395,541 | -8.49% | |
| Dimensional Fund Advisors Lp | 0.00% | 692,104 | $24,588,715 | $22,507,222 | -$2,081,493 | -8.47% | |
| Jefferies Financial Group Inc. | 0.31% | 647,391 | $23,001,802 | $21,053,155 | -$1,948,647 | -8.47% | |
| Acadian Asset Management Llc | 0.03% | 918,668 | $21,897,000 | $29,875,083 | +$7,978,083 | +36.43% | |
| Allianz Asset Management Gmbh | 0.02% | 879,258 | $20,970,303 | $28,593,470 | +$7,623,167 | +36.35% | |
| Mackenzie Financial Corp | 0.02% | 568,440 | $20,196,673 | $18,485,669 | -$1,711,004 | -8.47% | |
| Vanguard Portfolio Management Llc | 0.00% | 840,785 | $20,052,722 | $27,342,328 | +$7,289,606 | +36.35% | |
| Summit Partners Public Asset Management, Llc | 0.51% | 824,872 | $19,673,197 | $26,824,837 | +$7,151,640 | +36.35% | |
| State Street Corp | 0.00% | 822,079 | $19,630,772 | $26,734,009 | +$7,103,237 | +36.18% | |
| Qube Research & Technologies Ltd | 0.02% | 589,300 | $14,054,805 | $19,164,036 | +$5,109,231 | +36.35% | |
| Wasatch Advisors Lp | 0.07% | 279,343 | $9,925,057 | $9,084,234 | -$840,823 | -8.47% | |
| Kornitzer Capital Management Inc | 0.20% | 264,806 | $9,408,557 | $8,611,491 | -$797,066 | -8.47% | |
| Renaissance Technologies LLC | Jim Simons | 0.01% | 371,200 | $8,853,120 | $12,071,424 | +$3,218,304 | +36.35% |
| Allspring Global Investments Holdings, Llc | 0.01% | 244,962 | $8,703,500 | $7,966,164 | -$737,336 | -8.47% | |
| Goldman Sachs Group Inc | 0.00% | 358,397 | $8,547,768 | $11,655,070 | +$3,107,302 | +36.35% | |
| Point72 Asset Management, L.P. | 0.01% | 357,317 | $8,522,010 | $11,619,949 | +$3,097,939 | +36.35% | |
| Kennedy Capital Management Llc | 0.15% | 348,371 | $8,308,648 | $11,329,025 | +$3,020,377 | +36.35% | |
| Connor, Clark & Lunn Investment Management Ltd. | 0.01% | 331,727 | $7,911,689 | $10,787,762 | +$2,876,073 | +36.35% | |
| Morgan Stanley | 0.00% | 329,684 | $7,862,987 | $10,721,324 | +$2,858,337 | +36.35% | |
| Portolan Capital Management, Llc | 0.29% | 328,818 | $7,842,309 | $10,693,161 | +$2,850,852 | +36.35% | |
| Panagora Asset Management Inc | 0.02% | 301,040 | $7,179,804 | $9,789,821 | +$2,610,017 | +36.35% | |
| Northern Trust Corp | 0.00% | 285,158 | $6,801,019 | $9,273,338 | +$2,472,319 | +36.35% | |
| Citadel Advisors Llc | 0.00% | 265,353 | $6,328,669 | $8,629,280 | +$2,300,611 | +36.35% | |
| Silvercrest Asset Management Group Llc | 0.04% | 256,095 | $6,107,866 | $8,328,209 | +$2,220,343 | +36.35% | |
| Charles Schwab Investment Management Inc | 0.00% | 254,535 | $6,070,660 | $8,277,478 | +$2,206,818 | +36.35% | |
| Advisors Capital Management, Llc | 0.06% | 238,204 | $5,681,165 | $7,746,394 | +$2,065,229 | +36.35% | |
| New York State Common Retirement Fund | 0.01% | 234,746 | $5,598,692 | $7,633,940 | +$2,035,248 | +36.35% | |
| Palisade Capital Management, Lp | 0.24% | 231,931 | $5,531,554 | $7,542,396 | +$2,010,842 | +36.35% | |
| Nuveen, Llc | 0.00% | 231,726 | $5,526,666 | $7,535,730 | +$2,009,064 | +36.35% | |
| Bridgeway Capital Management, Llc | 0.09% | 221,338 | $5,278,911 | $7,197,912 | +$1,919,001 | +36.35% | |
| Trexquant Investment Lp | 0.03% | 206,111 | $4,915,747 | $6,702,730 | +$1,786,983 | +36.35% | |
| Millennium Management Llc | 0.00% | 205,369 | $4,898,051 | $6,678,600 | +$1,780,549 | +36.35% | |
| Vanguard Fiduciary Trust Co | 0.00% | 197,494 | $4,710,232 | $6,422,505 | +$1,712,273 | +36.35% | |
| Aqr Capital Management Llc | 0.00% | 166,567 | $3,972,623 | $5,416,759 | +$1,444,136 | +36.35% | |
| First Trust Advisors Lp | 0.00% | 145,064 | $3,459,776 | $4,717,481 | +$1,257,705 | +36.35% | |
| Parkman Healthcare Partners Llc | 0.35% | 144,791 | $3,453,265 | $4,708,603 | +$1,255,338 | +36.35% | |
| Empowered Funds, Llc | 0.02% | 142,338 | $3,394,761 | $4,628,832 | +$1,234,071 | +36.35% | |
| Bank Of New York Mellon Corp | 0.00% | 91,310 | $3,244,237 | $2,969,401 | -$274,836 | -8.47% | |
| Hrt Financial Lp | 0.01% | 115,853 | $2,763,000 | $3,767,540 | +$1,004,540 | +36.36% | |
| D. E. Shaw & Co., Inc. | 0.00% | 112,789 | $2,690,018 | $3,667,898 | +$977,880 | +36.35% | |
| Man Group Plc | 0.00% | 108,761 | $2,593,950 | $3,536,908 | +$942,958 | +36.35% | |
| Two Sigma Investments, Lp | 0.00% | 100,374 | $2,393,920 | $3,264,162 | +$870,242 | +36.35% | |
| Bank Of America Corp | 0.00% | 98,745 | $2,355,069 | $3,211,187 | +$856,118 | +36.35% | |
| Arrowstreet Capital, Limited Partnership | 0.00% | 92,736 | $2,211,754 | $3,015,775 | +$804,021 | +36.35% | |
| Ubs Group Ag | 0.00% | 89,368 | $2,131,427 | $2,906,247 | +$774,820 | +36.35% | |
| Jpmorgan Chase & Co | 0.00% | 84,804 | $2,062,434 | $2,757,826 | +$695,392 | +33.72% |
Frequently asked questions about CSTL
Who are the largest institutional holders of CSTL?
The largest institutional holders of CSTL reported in the latest SEC Form 13F filings include Blackrock, Inc., Rtw Investments, Lp, Principal Financial Group Inc, Vanguard Capital Management Llc, and Geode Capital Management, Llc. InsiderSet ranks institutional holders by their latest reported CSTL position.
What is CSTL institutional ownership?
This page tracks CSTL positions reported by institutional investment managers through SEC Form 13F. CASTLE BIOSCIENCES INC (CSTL) institutional ownership on InsiderSet reflects disclosed 13F holdings among the managers we analyze, not every shareholder of the stock.
How many institutions own CSTL?
InsiderSet currently tracks 181 institutional managers reporting CSTL holdings in the latest available 13F data. This count reflects institutions included in the SEC Form 13F filings analyzed by InsiderSet and should not be interpreted as the total number of CSTL shareholders.
How much CSTL stock do institutions own?
Institutional investment managers disclosed approximately $686.08M in CSTL holdings for Q2 2026. This figure is reported 13F value as of the filing period, not necessarily today's market value.
When was CSTL institutional ownership last updated?
The latest CSTL institutional ownership data on InsiderSet is based on SEC Form 13F filings for the quarter ended June 30, 2026. Form 13F filings are generally reported after the quarter ends, so the holdings shown represent the latest publicly disclosed positions rather than real-time institutional holdings.
Are institutional CSTL holdings real-time?
No. Form 13F data is not real-time. It represents positions reported by institutional investment managers as of the end of the reporting quarter. An institution may have changed its CSTL position after the reporting date.
Are institutions buying or selling CSTL?
Institutional buying and selling can be analyzed by comparing CSTL positions across consecutive 13F reporting periods. InsiderSet's CSTL Ownership Changes page shows institutions that increased, reduced, initiated, or exited positions based on reported 13F holdings. View CSTL ownership changes.
How has CSTL institutional ownership changed over time?
InsiderSet tracks CSTL institutional holdings across multiple 13F reporting periods, allowing investors to compare institutional holder counts, reported value, and reported shares over time.