Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Common Shares^F2	Apr 20, 2018	J	497,053	$0.00	D	2,238,979	I	See footnote
Common Shares^F4	Apr 20, 2018	J	2,947	$0.00	D	13,277	I	See footnote
Common Shares^F6	Apr 20, 2018	J	92,918	$0.00	A	92,918	I	See footnote
Common Shares^F6	Apr 20, 2018	J	92,918	$0.00	D	0	I	See footnote
Common Shares^F9,F10	Apr 23, 2018	S	89,628	$50.66	D	1,539,576	I	See footnote
Common Shares^F9,F12	Apr 23, 2018	S	2,630	$51.00	D	45,171	I	See footnote
Common Shares^F9,F14	Apr 23, 2018	S	2,915	$51.00	D	50,072	I	See footnote
Common Shares^F9,F16	Apr 23, 2018	S	6,821	$50.66	D	117,173	I	See footnote

Table II — derivative securities

No Table II lines on this filing.

Explanation of responses

F1Represents a pro-rata in-kind distribution of Common Stock of the Issuer by Versant Venture Capital IV, L.P. ("VVC IV") without consideration to its partners.
F10These securities are held of record by VVC V. Versant Ventures V, LLC ("VV V") is the sole general partner of VVC V and may be deemed to have voting and investment power over the securities held by VVC V and as a result may be deemed to have beneficial ownership over such securities, however, VV V disclaims beneficial ownership of the securities held by VVC V, except to the extent of its pecuniary interest therein.
F11The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by Versant Affiliates Fund V, L.P. ("VAF V").
F12These securities are held of record by VAF V. VV V is the sole general partner of VAF V and may be deemed to have voting and investment power over the securities held by VAF V and as a result may be deemed to have beneficial ownership over such securities, however, VV V disclaims beneficial ownership of the securities held by VAF V, except to the extent of its pecuniary interest therein.
F13The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by Versant Ophthalmic Affiliates Fund I, L.P. ("VOA").
F14These securities are held of record by VOA. VV V is the sole general partner of VOA and may be deemed to have voting and investment power over the securities held by VOA and as a result may be deemed to have beneficial ownership over such securities, however, VV V disclaims beneficial ownership of the securities held by VOA, except to the extent of its pecuniary interest therein.
F15The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by Versant Venture Capital V (Canada), L.P. ("VVC CAN").
F16These securities are held of record by VVC CAN. Versant Ventures V GP-GP (Canada), Inc. ("VV V CAN GP") is the sole general partner of Versant Ventures V (Canada), L.P. ("VV V CAN") and VV V CAN is the sole general partner of VVC CAN. VV V CAN GP and VV V CAN may be deemed to have voting and investment power over the securities held by VVC CAN and as a result may be deemed to have beneficial ownership over such securities, however, VV V CAN GP and VV V CAN each disclaim beneficial ownership of the securities held by VVC CAN, except to the extent of their pecuniary interests therein.
F2These securities are held of record by VVC IV. Versant Ventures IV, LLC ("VV IV") is the sole general partner of VVC IV and may be deemed to have voting and investment power over the securities held by VVC IV and as a result may be deemed to have beneficial ownership over such securities, however, VV IV disclaims beneficial ownership of the securities held by VVC IV, except to the extent of its pecuniary interest therein.
F3Represents a pro-rata in-kind distribution of Common Stock of the Issuer by Versant Side Fund IV, L.P. ("VSF IV") without consideration to its partners.
F4These securities are held of record by VSF IV. VV IV is the sole general partner of VSF IV and may be deemed to have voting and investment power over the securities held by VSF IV and as a result may be deemed to have beneficial ownership over such securities, however, VV IV disclaims beneficial ownership of the securities held by VSF IV, except to the extent of its pecuniary interest therein.
F5Represents a change in the form of ownership of VV IV by virtue of the receipt of shares in the pro-rata in-kind distribution of Common Stock of the Issuer for no consideration by VVC IV and VSF IV.
F6The shares are held by VV IV.
F7Represents a pro-rata in-kind distribution of Common Stock of the Issuer by VV IV without consideration to its members.
F8The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by Versant Venture Capital V, L.P. ("VVC V").
F9The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $50.00 to $54.00 per share, inclusive. The reporting person undertakes to provide to CRISPR Therapeutics AG, any security holder of CRISPR Therapeutics AG, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth herein.