CASTLE BIOSCIENCES INC — Director's Dealing 2020

May 28, 2020

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: CASTLE BIOSCIENCES INC (CSTL)
CIK: 0001447362
Period of Report: 2020-05-26

Reporting Person: Cook Joseph C. III (Director, 10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2020-05-26	Common Stock	S	2099	$37.28	Disposed	1668119	Indirect
2020-05-26	Common Stock	S	16924	$38.72	Disposed	1651195	Indirect
2020-05-26	Common Stock	S	4797	$39.19	Disposed	1646398	Indirect
2020-05-27	Common Stock	S	10630	$37.38	Disposed	1635768	Indirect
2020-05-27	Common Stock	S	1884	$38.17	Disposed	1633884	Indirect

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	208053	Direct

Footnotes

F1: The transactions on this Form 4 were made pursuant to a Rule 10b5-1 plan adopted by MGC Venture Partners 2013, L.P. ("MGC 2013 LP") on March 13, 2020.

F2: This transaction was executed in multiple trades at prices ranging from $37.00 to $37.68, 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.

F3: Held by MGC 2013 LP, MGC Venture Partners 2018, L.P. ("MGC 2018 LP") and MGC Venture Partners QP 2018, L.P. ("MGC 2018 QP LP"). MGC Venture Partners 2013 GP, LLC ("MGC 2013 GP") is the general partner of MGC 2013 LP. MGC Venture Partners 2018 GP, LLC ("MGC 2018 GP") is the general partner of MGC 2018 LP and MGC 2018 QP LP.

F4: The Reporting Person is a managing director of MGC 2013 GP and a managing partner of MGC 2018 GP, and shares voting and investment power over the shares held by MGC 2013 LP, MGC 2018 LP and MGC 2018 QP LP. The Reporting Person disclaims beneficial ownership of the shares held by MGC 2013 GP, MGC 2018 GP, MGC 2013 LP, MGC 2018 LP and MGC 2018 QP LP as reported herein, except to the extent of his pecuniary interest therein, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of such securities for purposes of Section 16 or for any other purposes.

F5: This transaction was executed in multiple trades at prices ranging from $38.04 to $39.03, 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.

F6: This transaction was executed in multiple trades at prices ranging from $39.04 to $39.58, 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.

F7: This transaction was executed in multiple trades at prices ranging from $37.00 to $37.99, 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.

F8: This transaction was executed in multiple trades at prices ranging from $38.00 to $38.44, 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.