CSTLNasdaqServices-Medical LaboratoriesFiscal year ends December 31
CASTLE BIOSCIENCES INC
Financials through Q2 FY2026, quarter ended Jun 30, 2026Last filing: 10-Q on Jul 30, 2026
$32.16+0.20 (+0.64%)
Close on Oct 19, 2026
- Market cap
- $977.78M
- P/E (TTM)
- –
- Dividend yield
- 0.00%
Ownership
Institutional holdings as of Jun 30, 2026, from 13F filings
Held by institutions
89.5%
27M of 31M shares
Institutional holders
176
24 new, 30 sold out
Net institutional buying
-0M
In Q2 2026
Insider trades, 12 months
0 buys · 207 sales
Net sold $17.98M
Shares held by institutions
Holders of more than 5%
Latest Schedule 13D (active) or 13G (passive) filed by each holder
| Holder | Shares | % of class | Filing | As of |
|---|---|---|---|---|
| RTW Investments, LP | 2,758,335 | 9.30% | 13G (passive) amendment | Mar 31, 2026 |
| BlackRock, Inc. | 2,338,005 | 8.20% | 13G (passive) amendment | Mar 31, 2025 |
| Roderick Wong | 2,115,237 | 7.20% | 13G (passive) | Dec 31, 2025 |
| Principal Global Investors, LLC | 1,585,639 | 5.89% | 13G (passive) | Dec 31, 2023 |
Top institutional holders
13F holdings as of Jun 30, 2026
| Holder | Shares | % of CSTL | Value | Change | % of portfolio |
|---|---|---|---|---|---|
| BlackRock, Inc. | 3,291,963 | 10.78% | $78.51M | +309,017 | 0.00% |
| Rtw Investments, LP | 2,778,335 | 9.09% | $66.26M | +20,000 | 0.57% |
| Principal Financial Group Inc | 1,726,648 | 5.65% | $41.18M | −43,229 | 0.02% |
| Vanguard Capital Management LLC | 1,226,497 | 4.01% | $29.25M | +48,975 | 0.00% |
| Acadian Asset Management LLC | 918,668 | 3.01% | $21.90K | +434,227 | 0.03% |
| Vanguard Portfolio Management LLC | 840,785 | 2.75% | $20.05M | −20,986 | 0.00% |
| Summit Partners Public Asset Management, LLC | 824,872 | 2.70% | $19.67M | −115,813 | 0.35% |
| State Street Corp | 822,079 | 2.69% | $19.63M | +53,000 | 0.00% |
| Allianz Asset Management GmbH | 811,324 | 2.66% | $19.92M | – | 0.02% |
| Geode Capital Management, LLC | 795,912 | 2.61% | $18.99M | +67,812 | 0.00% |
| Mackenzie Financial Corp | 793,507 | 2.60% | $18.93M | +719,396 | 0.02% |
| Dimensional Fund Advisors LP | 791,085 | 2.59% | $18.87M | −248,676 | 0.00% |
| Jefferies Financial Group Inc. | 647,391 | 2.12% | $15.44M | New | 0.10% |
| Qube Research & Technologies Ltd | 589,300 | 1.93% | $14.05M | +29,717 | 0.01% |
| AIGH Capital Management LLC | 545,101 | 1.78% | $13.00M | −45,500 | 0.82% |
| Renaissance Technologies LLC | 371,200 | 1.22% | $8.85M | −161,600 | 0.01% |
| Goldman Sachs Group Inc | 358,397 | 1.17% | $8.55M | +17,226 | 0.00% |
| Point72 Asset Management, L.P. | 357,317 | 1.17% | $8.52M | New | 0.01% |
| Kennedy Capital Management LLC | 348,371 | 1.14% | $8.31M | New | 0.15% |
| Connor, Clark & Lunn Investment Management Ltd. | 331,727 | 1.09% | $7.91M | −45,355 | 0.01% |
Institutional buying and selling by quarter
Positions opened, added to, reduced and closed by 13F filers
| Quarter | Holders | Shares held | % of shares | New / added | Reduced / closed | Shares bought | Shares sold |
|---|---|---|---|---|---|---|---|
| Q2 2026 | 176 | 27M | 89.5% | 24 / 79 | 56 / 30 | 5M | 5M |
| Q1 2026 | 186 | 28M | 90.4% | 29 / 72 | 61 / 36 | 6M | 3M |
| Q4 2025 | 195 | 27M | 89.5% | 43 / 65 | 68 / 17 | 5M | 4M |
| Q3 2025 | 173 | 27M | 87.3% | 37 / 62 | 53 / 15 | 3M | 3M |
| Q2 2025 | 152 | 27M | 86.9% | 16 / 69 | 45 / 42 | 4M | 4M |
| Q1 2025 | 180 | 26M | 84.9% | 30 / 74 | 56 / 44 | 6M | 6M |
| Q4 2024 | 197 | 27M | 87.2% | 40 / 66 | 66 / 27 | 5M | 4M |
| Q3 2024 | 185 | 26M | 84.9% | 43 / 75 | 47 / 16 | 7M | 3M |
| Q2 2024 | 159 | 25M | 82.8% | 32 / 54 | 50 / 23 | 3M | 4M |
| Q1 2024 | 151 | 26M | 86.3% | 18 / 54 | 55 / 17 | 4M | 2M |
| Q4 2023 | 153 | 24M | 79.9% | 37 / 56 | 44 / 18 | 4M | 2M |
| Q3 2023 | 135 | 23M | 75.8% | 22 / 52 | 41 / 16 | 3M | 3M |
Top mutual fund and ETF holders
Latest monthly portfolio reports (Form N-PORT)
| Fund | Shares | % of CSTL | Value | % of fund | As of |
|---|---|---|---|---|---|
| Vanguard Total Stock Market Index Fund | 852,704 | 2.79% | $20.34M | 0.00% | Jun 30, 2026 |
| iShares Russell 2000 ETF | 781,367 | 2.56% | $18.64M | 0.02% | Jun 30, 2026 |
| SmallCap Fund | 725,138 | 2.37% | $20.30M | 0.97% | Jul 31, 2026 |
| Vanguard Extended Market Index Fund | 342,655 | 1.12% | $8.17M | 0.01% | Jun 30, 2026 |
| Fidelity Small Cap Index Fund | 327,806 | 1.07% | $9.18M | 0.03% | Jul 31, 2026 |
| Strategic Advisers U.S. Total Stock Fund | 312,066 | 1.02% | $6.58M | 0.01% | May 31, 2026 |
| iShares Russell 2000 Value ETF | 278,685 | 0.91% | $6.65M | 0.05% | Jun 30, 2026 |
| Wasatch Micro Cap Fund | 276,685 | 0.91% | $6.60M | 0.98% | Jun 30, 2026 |
| Vanguard Explorer Fund | 275,891 | 0.90% | $7.72M | 0.03% | Jul 31, 2026 |
| Buffalo Small Cap Growth Fund | 239,614 | 0.78% | $5.71M | 1.22% | Jun 30, 2026 |
| iShares Biotechnology ETF | 208,267 | 0.68% | $4.97M | 0.05% | Jun 30, 2026 |
| Vanguard Strategic Small-Cap Equity Fund | 179,326 | 0.59% | $4.28M | 0.14% | Jun 30, 2026 |
| Fidelity Extended Market Index Fund | 151,700 | 0.50% | $3.20M | 0.01% | May 31, 2026 |
| BlackRock Advantage Small Cap Core Fund | 151,572 | 0.50% | $3.20M | 0.06% | May 29, 2026 |
| Vanguard Russell 2000 Index Fund | 147,766 | 0.48% | $3.11M | 0.02% | May 31, 2026 |
Officers, directors and major owners
People who filed Forms 3, 4 or 5 in the last two years
| Name | Role | Shares owned | % of shares | Latest filing |
|---|---|---|---|---|
| Derek J. Maetzold | Pres. & Chief Exec. Officer, Director | 181,715 | 0.59% | Sep 23, 2026 |
| Tobin W. Juvenal | Chief Commercial Officer | 60,814 | 0.20% | Sep 16, 2026 |
| Kristen M. Oelschlager | Chief Operating Officer | 90,157 | 0.30% | Sep 3, 2026 |
| Frank Stokes | Chief Financial Officer | 35,177 | 0.12% | Aug 18, 2026 |
| Ellen Goldberg | Director | 40,921 | 0.13% | Jun 1, 2026 |
| Kim Caple | Director | 36,121 | 0.12% | Jun 1, 2026 |
| G. Bradley Cole | Director | 32,976 | 0.11% | Jun 1, 2026 |
| Rodney Cotton | Director | 32,998 | 0.11% | Jun 1, 2026 |
| Daniel Bradbury | Director | 35,631 | 0.12% | Jun 1, 2026 |
| Miles Harrison | Director | 35,631 | 0.12% | Jun 1, 2026 |
| Tiffany Olson | Director | 39,573 | 0.13% | Jun 1, 2026 |
Insider trades
Common stock transactions reported on Form 4, newest first
| Insider | Date | Transaction | Shares | Price | Value | Shares after |
|---|---|---|---|---|---|---|
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Sep 21, 2026 | Sale(10b5-1 plan) | −8,580 | $35.33 | $303.13K | 21,479 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Sep 21, 2026 | Option exercise | +8,580 | $2.39 | $20.51K | 30,059 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Sep 21, 2026 | Sale(10b5-1 plan) | −3,198 | $35.33 | $112.99K | 11,236 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Sep 21, 2026 | Sale(10b5-1 plan) | −2,718 | $35.33 | $96.03K | 9,550 |
| Tobin W. Juvenal Chief Commercial Officer | Sep 15, 2026 | Sale(10b5-1 plan) | −3,294 | $35.14 | $115.75K | 58,584 |
| Tobin W. Juvenal Chief Commercial Officer | Sep 14, 2026 | Sale(10b5-1 plan) | −3,306 | $32.32 | $106.85K | 61,878 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Sep 11, 2026 | Sale(10b5-1 plan) | −223 | $32.78 | $7.31K | 21,479 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Sep 11, 2026 | Sale(10b5-1 plan) | −83 | $32.78 | $2.72K | 14,434 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Sep 11, 2026 | Sale(10b5-1 plan) | −71 | $32.78 | $2.33K | 12,268 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Sep 11, 2026 | Sale(10b5-1 plan) | −2,656 | $32.00 | $84.99K | 12,339 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Sep 11, 2026 | Sale(10b5-1 plan) | −3,124 | $32.00 | $99.97K | 14,517 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Sep 11, 2026 | Sale(10b5-1 plan) | −8,361 | $32.00 | $267.55K | 21,702 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Sep 11, 2026 | Option exercise | +8,584 | $2.39 | $20.52K | 30,063 |
| Kristen M. Oelschlager Chief Operating Officer | Sep 1, 2026 | Option exercise | +4,152 | $3.38 | $14.03K | 17,508 |
| Kristen M. Oelschlager Chief Operating Officer | Sep 1, 2026 | Sale(10b5-1 plan) | −3,952 | $33.36 | $131.84K | 13,556 |
| Kristen M. Oelschlager Chief Operating Officer | Sep 1, 2026 | Sale(10b5-1 plan) | −200 | $34.02 | $6.80K | 13,356 |
| Tobin W. Juvenal Chief Commercial Officer | Aug 31, 2026 | Sale(10b5-1 plan) | −1,730 | $32.81 | $56.76K | 65,184 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Sale(10b5-1 plan) | −257 | $33.14 | $8.52K | 11,277 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Option exercise | +12,428 | $2.39 | $29.70K | 33,907 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Sale(10b5-1 plan) | −11,472 | $33.14 | $380.18K | 22,435 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Sale(10b5-1 plan) | −21 | $33.88 | $711 | 11,256 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Sale(10b5-1 plan) | −21 | $33.88 | $711 | 11,256 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Sale(10b5-1 plan) | −21 | $33.88 | $711 | 11,256 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Sale(10b5-1 plan) | −177 | $33.88 | $6.00K | 14,995 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Sale(10b5-1 plan) | −209 | $33.88 | $7.08K | 17,641 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Sale(10b5-1 plan) | −956 | $33.88 | $32.39K | 21,479 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Sale(10b5-1 plan) | −257 | $33.14 | $8.52K | 11,277 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Sale(10b5-1 plan) | −21 | $33.88 | $711 | 11,256 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Sale(10b5-1 plan) | −257 | $33.14 | $8.52K | 11,277 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Sale(10b5-1 plan) | −257 | $33.14 | $8.52K | 11,277 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Sale(10b5-1 plan) | −2,129 | $33.14 | $70.56K | 15,172 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 28, 2026 | Sale(10b5-1 plan) | −2,505 | $33.14 | $83.02K | 17,850 |
| Tobin W. Juvenal Chief Commercial Officer | Aug 25, 2026 | Sale(10b5-1 plan) | −9,050 | $35.04 | $317.11K | 66,914 |
| Kristen M. Oelschlager Chief Operating Officer | Aug 25, 2026 | Sale | −5,223 | $34.64 | $180.92K | 72,649 |
| Kristen M. Oelschlager Chief Operating Officer | Aug 25, 2026 | Sale | −7,161 | $34.26 | $245.34K | 77,872 |
| Kristen M. Oelschlager Chief Operating Officer | Aug 24, 2026 | Sale | −12,218 | $33.69 | $411.62K | 85,033 |
| Tobin W. Juvenal Chief Commercial Officer | Aug 17, 2026 | Sale(10b5-1 plan) | −1,730 | $29.59 | $51.19K | 75,964 |
| Frank Stokes Chief Financial Officer | Aug 14, 2026 | Sale | −24,908 | $29.77 | $741.51K | 35,177 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 14, 2026 | Sale(10b5-1 plan) | −278 | $30.02 | $8.35K | 11,534 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 14, 2026 | Sale(10b5-1 plan) | −278 | $30.02 | $8.35K | 11,534 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 14, 2026 | Sale(10b5-1 plan) | −278 | $30.02 | $8.35K | 11,534 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 14, 2026 | Sale(10b5-1 plan) | −278 | $30.02 | $8.35K | 11,534 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 14, 2026 | Sale(10b5-1 plan) | −2,306 | $30.02 | $69.23K | 17,301 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 14, 2026 | Sale(10b5-1 plan) | −2,714 | $30.02 | $81.47K | 20,355 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 14, 2026 | Sale(10b5-1 plan) | −1,100 | $30.02 | $33.02K | 21,479 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 14, 2026 | Option exercise | +1,100 | $2.39 | $2.63K | 22,579 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 5, 2026 | Sale(10b5-1 plan) | −473 | $30.68 | $14.51K | 19,607 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 5, 2026 | Sale(10b5-1 plan) | −556 | $30.68 | $17.06K | 23,069 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 5, 2026 | Sale(10b5-1 plan) | −2,546 | $30.68 | $78.11K | 21,479 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 5, 2026 | Option exercise | +2,546 | $2.39 | $6.08K | 24,025 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 4, 2026 | Option exercise | +20,356 | $2.39 | $48.65K | 41,835 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 4, 2026 | Sale(10b5-1 plan) | −8,421 | $30.79 | $259.28K | 33,414 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 4, 2026 | Sale(10b5-1 plan) | −3,374 | $30.79 | $103.89K | 28,407 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 4, 2026 | Sale(10b5-1 plan) | −2,866 | $30.79 | $88.24K | 24,143 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 4, 2026 | Sale(10b5-1 plan) | −4,063 | $31.34 | $127.33K | 20,080 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 4, 2026 | Sale(10b5-1 plan) | −4,782 | $31.34 | $149.87K | 23,625 |
| Derek J. Maetzold Pres. & Chief Exec. Officer, Director | Aug 4, 2026 | Sale(10b5-1 plan) | −11,935 | $31.34 | $374.04K | 21,479 |
| Kristen M. Oelschlager Chief Operating Officer | Aug 3, 2026 | Sale(10b5-1 plan) | −4,486 | $30.00 | $134.58K | 14,388 |
| Kristen M. Oelschlager Chief Operating Officer | Aug 3, 2026 | Sale(10b5-1 plan) | −3,000 | $29.12 | $87.36K | 18,874 |
| Kristen M. Oelschlager Chief Operating Officer | Aug 3, 2026 | Sale(10b5-1 plan) | −1,100 | $30.62 | $33.68K | 13,288 |
Awards, option exercises, tax withholding and gifts are shown alongside open-market buys and sales. Each name links to the filing on SEC EDGAR.
Planned insider sales
Notices of proposed sale filed on Form 144 before shares are sold
| Seller | Filed | Shares | Market value | Planned sale | Acquired through |
|---|---|---|---|---|---|
| Juvenal Tobin Chief Commercial Officer | Oct 13, 2026 | 13,154 | $430.93K | Oct 12, 2026 | Acquired as compensation -- Restricted Stock Units |
| Maetzold Derek Officer | Oct 5, 2026 | 28,992 | $1.06M | Oct 5, 2026 | Acquired as a gift |
| Oelschlager Kristen Officer | Oct 1, 2026 | 4,153 | $147.56K | Oct 1, 2026 | Exercise of Stock Options |
| Juvenal Tobin Chief Commercial Officer | Sep 14, 2026 | 13,177 | $440.64K | Sep 14, 2026 | Acquired as compensation -- Restricted Stock Units |
| Maetzold Derek Officer | Sep 11, 2026 | 29,014 | $938.02K | Sep 11, 2026 | Acquired as a gift |
| Juvenal Tobin Chief Commercial Officer | Aug 25, 2026 | 22,500 | $787.50K | Aug 25, 2026 | Acquired as compensation -- Restricted Stock Units |
| M. Oelschlager Kristen Officer | Aug 24, 2026 | 24,602 | $841.39K | Aug 24, 2026 | Retitled existing joint account into trust name |
| M. Stokes Franklin Officer | Aug 14, 2026 | 24,908 | $741.49K | Aug 14, 2026 | Restricted Stock |
| Maetzold Derek Officer | Aug 14, 2026 | 25,792 | $763.96K | Aug 14, 2026 | Acquired as gift |
| Juvenal Tobin Chief Commercial Officer | Jul 31, 2026 | 22,500 | $630.00K | Jul 31, 2026 | Acquired as compensation -- Restricted Stock Units |
| Maetzold Derek Officer | Jul 31, 2026 | 67,662 | $1.89M | Jul 31, 2026 | Acquired as gift |
| Maetzold Derek Officer | Jul 1, 2026 | 23,844 | $589.19K | Jul 1, 2026 | Acquired as gift |
| Oelschlager Kristen Officer | Jun 16, 2026 | 29,911 | $617.96K | Jun 16, 2026 | Exercise of Stock Options |
| Maetzold Derek Officer | Jun 1, 2026 | 14,008 | $293.75K | Jun 1, 2026 | Acquired as gift |
| Maetzold Derek Officer | May 7, 2026 | 14,008 | $269.51K | May 7, 2026 | Acquired as gift |