Mark C. McKenna - 01 Dec 2021 Form 4 Insider Report for Prometheus Biosciences, Inc.

Role: Chairman, President & CEO, Director
Signature: /s/ Timothy K. Andrews, attorney-in-fact for Mark C. McKenna
Issuer symbol: N/A
Transactions as of: 01 Dec 2021
Net transactions value: +$44,660
Form type: 4
Filing time: 03 Dec 2021, 18:02:37 UTC
Previous filing: 16 Nov 2021
Next filing: 20 May 2022
SEC: View on sec.gov

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	RXDX	Common Stock	Options Exercise	$44,660	+15,400		$2.90^*	15,400	01 Dec 2021	Direct

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	RXDX	Stock Option (Right to Buy)	Options Exercise	$0	-15,400	-11%	$0.000000	122,531	01 Dec 2021	Common Stock	15,400	$2.90	Direct	F1

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	25% of the shares subject to the option vested on September 9, 2020, and 1/48th of the shares subject to the option vest monthly thereafter, subject to the Reporting Person's continued service with the Issuer through each vest date.