CSTL · Castle Biosciences Inc

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $22.62 to $23.15, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $22.62 to $23.15, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold 2018 Remainder Trust FBO John Derek Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $22.62 to $23.15, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

The shares subject to the option are fully vested.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $22.62 to $23.15, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by Derek Maetzold 2020 Irrevocable Trust of which the Reporting Person is the trustee and his children are beneficiaries.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $22.62 to $23.15, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold Descendants 2020 Trust of which the Reporting Person's spouse is the trustee and the Reporting Person's spouse and their children are beneficiaries.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $22.62 to $23.15, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $22.62 to $23.15, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person, on March 17, 2026.

This transaction was executed in multiple trades at prices ranging from $24.77 to $24.79, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $23.68 to $24.57, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $23.68 to $24.57, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold Descendants 2020 Trust of which the Reporting Person's spouse is the trustee and the Reporting Person's spouse and their children are beneficiaries.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $23.68 to $24.57, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

The shares subject to the option are fully vested.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $23.68 to $24.57, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $23.68 to $24.57, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold 2018 Remainder Trust FBO John Derek Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $23.68 to $24.57, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $23.68 to $24.57, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by Derek Maetzold 2020 Irrevocable Trust of which the Reporting Person is the trustee and his children are beneficiaries.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person, on March 17, 2026.

This transaction was executed in multiple trades at prices ranging from $23.73 to $24.72, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person, on March 17, 2026.

This transaction was executed in multiple trades at prices ranging from $20.51 to $20.95, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $20.44 to $20.98, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Reflects the transfers on June 10, 2026, of 45,024 shares of common stock from DJM Grantor Annuity Trust No. 5, of which, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO John Derek Maetzold and 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold. The remaining 40,935 shares of common stock held by DJM Grantor Annuity Trust No. 5 were transferred as described in footnote 12, after which DJM Grantor Annuity Trust No. 5 holds no remaining shares of common stock.

Held by The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $20.44 to $20.98, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Reflects the transfers on June 10, 2026, of 45,024 shares of common stock from DJM Grantor Annuity Trust No. 5, of which, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO John Derek Maetzold and 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold. The remaining 40,935 shares of common stock held by DJM Grantor Annuity Trust No. 5 were transferred as described in footnote 12, after which DJM Grantor Annuity Trust No. 5 holds no remaining shares of common stock.

Held by The Maetzold 2018 Remainder Trust FBO John Derek Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $20.44 to $20.98, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Reflects the transfers on June 10, 2026, of 45,024 shares of common stock from DJM Grantor Annuity Trust No. 5, of which, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO John Derek Maetzold and 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold. The remaining 40,935 shares of common stock held by DJM Grantor Annuity Trust No. 5 were transferred as described in footnote 12, after which DJM Grantor Annuity Trust No. 5 holds no remaining shares of common stock.

Held by The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $20.44 to $20.98, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by Derek Maetzold 2020 Irrevocable Trust of which the Reporting Person is the trustee and his children are beneficiaries.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $20.44 to $20.98, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold Descendants 2020 Trust of which the Reporting Person's spouse is the trustee and the Reporting Person's spouse and their children are beneficiaries.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $20.44 to $20.98, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $20.44 to $20.98, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Reflects the transfers on June 10, 2026, of 45,024 shares of common stock from DJM Grantor Annuity Trust No. 5, of which, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold, 11,256 transferred to The Maetzold 2018 Remainder Trust FBO John Derek Maetzold and 11,256 transferred to The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold. The remaining 40,935 shares of common stock held by DJM Grantor Annuity Trust No. 5 were transferred as described in footnote 12, after which DJM Grantor Annuity Trust No. 5 holds no remaining shares of common stock.

Held by The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

The shares subject to the option are fully vested.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $20.470 to $21.175, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold Descendants 2020 Trust of which the Reporting Person's spouse is the trustee and the Reporting Person's spouse and their children are beneficiaries.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $20.470 to $21.175, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

The shares subject to the option are fully vested.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $20.470 to $21.175, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

The shares subject to the option are fully vested.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $20.470 to $21.175, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $20.470 to $21.175, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by Derek Maetzold 2020 Irrevocable Trust of which the Reporting Person is the trustee and his children are beneficiaries.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $20.470 to $21.175, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold 2018 Remainder Trust FBO John Derek Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 3, 2025.

This transaction was executed in multiple trades at prices ranging from $20.470 to $21.175, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Held by The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk of which the Reporting Person is the trustee and his child is the beneficiary.

Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock.

The RSUs vest in full on the earlier of the (a) one-year anniversary of the date on May 28, 2027, or (b) the day immediately preceding the next Annual Meeting of Stockholders following the date of the grant.

Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock.

The RSUs vest in full on the earlier of the (a) one-year anniversary of the date on May 28, 2027, or (b) the day immediately preceding the next Annual Meeting of Stockholders following the date of the grant.

Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock.

The RSUs vest in full on the earlier of the (a) one-year anniversary of the date on May 28, 2027, or (b) the day immediately preceding the next Annual Meeting of Stockholders following the date of the grant.

Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock.

The RSUs vest in full on the earlier of the (a) one-year anniversary of the date on May 28, 2027, or (b) the day immediately preceding the next Annual Meeting of Stockholders following the date of the grant.

Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock.

The RSUs vest in full on the earlier of the (a) one-year anniversary of the date on May 28, 2027, or (b) the day immediately preceding the next Annual Meeting of Stockholders following the date of the grant.

Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock.

The RSUs vest in full on the earlier of the (a) one-year anniversary of the date on May 28, 2027, or (b) the day immediately preceding the next Annual Meeting of Stockholders following the date of the grant.

Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock.

The RSUs vest in full on the earlier of the (a) one-year anniversary of the date on May 28, 2027, or (b) the day immediately preceding the next Annual Meeting of Stockholders following the date of the grant.

Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock.

Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock.

The RSUs vest in full on the earlier of the (a) one-year anniversary of the date on May 22, 2026, or (b) the day immediately preceding the next Annual Meeting of Stockholders following the date of the grant.