CSTL · Insider trading · 13F holders · Congress trades
Castle Biosciences Inc (CSTL)
Who is buying and selling CSTL: company insiders on SEC Form 4, hedge funds and superinvestors on Form 13F, and members of Congress under the STOCK Act. Every figure links to the filing or page it comes from.
- 13F filers holding
- 2
- Insider buys, 90 days
- $0
- Insider sales, 90 days
- $8.7M
- Congress trades, 12 months
- 1
CSTL at a glance
- Between Aug 1, 2026 and Oct 29, 2026, 4 CSTL insiders filed 22 sales worth $8.7M on SEC Form 4, and no open-market purchases; 20 of the sales were pre-planned under Rule 10b5-1.
- 2 13F filers hold CSTL among their 50 largest positions, worth $79.3M combined. The biggest bets by portfolio weight are AIGH Capital Management LLC (1.2%) and Rtw Investments, LP (0.6%).
- Members of Congress have disclosed 3 CSTL trades since 2020, 0 purchases and 1 sale in the past year; the latest was Josh Gottheimer (D-NJ), selling $1K–15K on Mar 15, 2022.
- CSTL last closed at $38.51 on Oct 29, 2026.
CSTL insider trading
Between Aug 1, 2026 and Oct 29, 2026, 4 CSTL insiders filed 22 sales worth $8.7M on SEC Form 4, and no open-market purchases; 20 of the sales were pre-planned under Rule 10b5-1.
| Filed | Insider | Role | Trade | Shares | Price | Value | Form 4 |
|---|---|---|---|---|---|---|---|
| Oct 28, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sale10b5-1 | 3,288 | $33.08 | $109K | SEC |
| Oct 21, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer, Director | Sale10b5-1 | 14,496 | $31.91 | $463K | SEC |
| Oct 14, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sale10b5-1 | 3,288 | $33.64 | $111K | SEC |
| Oct 7, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer, Director | Sale10b5-1 | 14,496 | $35.57 | $516K | SEC |
| Oct 5, 2026 | Oelschlager Kristen M | Chief Operating Officer | Sale10b5-1 | 4,153 | $35.95 | $149K | SEC |
| Oct 1, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sale10b5-1 | 6,577 | $35.29 | $232K | SEC |
| Sep 23, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer, Director | Sale10b5-1 | 14,496 | $35.33 | $512K | SEC |
| Sep 16, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sale10b5-1 | 6,600 | $33.73 | $223K | SEC |
| Sep 15, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer, Director | Sale10b5-1 | 14,518 | $32.02 | $465K | SEC |
| Sep 3, 2026 | Oelschlager Kristen M | Chief Operating Officer | Sale10b5-1 | 4,152 | $33.39 | $139K | SEC |
| Sep 2, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sale10b5-1 | 1,730 | $32.81 | $57K | SEC |
| Sep 1, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer, Director | Sale10b5-1 | 18,560 | $33.20 | $616K | SEC |
| Aug 27, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sale10b5-1 | 9,050 | $35.04 | $317K | SEC |
| Aug 26, 2026 | Oelschlager Kristen M | Chief Operating Officer | Sale | 24,602 | $34.06 | $838K | SEC |
| Aug 19, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sale10b5-1 | 1,730 | $29.59 | $51K | SEC |
| Aug 18, 2026 | Stokes Frank | Chief Financial Officer | Sale | 24,908 | $29.77 | $742K | SEC |
| Aug 18, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer, Director | Sale10b5-1 | 7,232 | $30.02 | $217K | SEC |
| Aug 6, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer, Director | Sale10b5-1 | 39,016 | $31.07 | $1.2M | SEC |
| Aug 6, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sale10b5-1 | 1,301 | $38.39 | $50K | SEC |
| Aug 5, 2026 | Oelschlager Kristen M | Chief Operating Officer | Sale10b5-1 | 8,586 | $29.77 | $256K | SEC |
| Aug 4, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer, Director | Sale10b5-1 | 28,646 | $30.28 | $867K | SEC |
| Aug 4, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sale10b5-1 | 19,040 | $29.21 | $556K | SEC |
Who owns CSTL? Hedge funds and superinvestors
2 13F filers hold CSTL among their 50 largest positions, worth $79.3M combined. The biggest bets by portfolio weight are AIGH Capital Management LLC (1.2%) and Rtw Investments, LP (0.6%).
| Manager | % of portfolio | Value | Shares | Last quarter | 13F |
|---|---|---|---|---|---|
| Rtw Investments, LPHedge fund | 0.6% | $66.3M | 2,778,335 | +0.7% shares | Q2 2026 |
| AIGH Capital Management LLCHedge fund | 1.2% | $13.0M | 545,101 | -7.7% shares | Q2 2026 |
Each manager counts with its latest 13F (Q2 2026: 2). Screen CSTL in the grand portfolio →
CSTL stock trades by members of Congress
Members of Congress have disclosed 3 CSTL trades since 2020, 0 purchases and 1 sale in the past year; the latest was Josh Gottheimer (D-NJ), selling $1K–15K on Mar 15, 2022.
| Filed | Member | Trade | Amount | Traded | Since |
|---|---|---|---|---|---|
| Apr 17, 2022 | Josh GottheimerD-NJ · House | Sale | $1K–15K | Mar 15, 2022 | +3.8% |
| Jan 11, 2021 | Gilbert Ray Cisneros, Jr.D-CA · House | Buy | $1K–15K | Dec 23, 2020 | -47.5% |
| Jan 7, 2021 | Josh GottheimerD-NJ · House | Buy | $1K–15K | Dec 21, 2020 | -47.3% |
2 members have traded CSTL: Josh Gottheimer, Gilbert Ray Cisneros, Jr..
CSTL questions and answers
Are insiders buying CSTL stock?
Between Aug 1, 2026 and Oct 29, 2026, 4 CSTL insiders filed 22 sales worth $8.7M on SEC Form 4, and no open-market purchases; 20 of the sales were pre-planned under Rule 10b5-1.
Which hedge funds own CSTL?
2 13F filers hold CSTL among their 50 largest positions, worth $79.3M combined. The biggest bets by portfolio weight are AIGH Capital Management LLC (1.2%) and Rtw Investments, LP (0.6%).
Has Congress traded CSTL?
Members of Congress have disclosed 3 CSTL trades since 2020, 0 purchases and 1 sale in the past year; the latest was Josh Gottheimer (D-NJ), selling $1K–15K on Mar 15, 2022.
Who is the largest holder of CSTL?
Among 13F filers, Rtw Investments, LP reports the largest CSTL position, $66.3M (2,778,335 shares) in its Q2 2026 13F. The biggest bet by portfolio weight is AIGH Capital Management LLC's: 1.2% of its portfolio.
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