X0306 4 2021-03-23 0 0001674416 CRISPR Therapeutics AG CRSP 0001762583 Klein Lawrence Otto C/O CRISPR THERAPEUTICS, INC. 610 MAIN STREET CAMBRIDGE MA 02139 0 1 0 0 CBO & COO Common Shares 2021-03-23 4 M 0 12000 44.67 A 25050 D Common Shares 2021-03-23 4 M 0 22000 51.49 A 47050 D Common Shares 2021-03-23 4 M 0 10000 29.87 A 57050 D Common Shares 2021-03-23 4 M 0 20000 40.87 A 77050 D Common Shares 2021-03-23 4 M 0 12000 14.43 A 89050 D Common Shares 2021-03-23 4 M 0 12000 17.66 A 101050 D Common Shares 2021-03-23 4 S 0 88000 128.20 D 13050 D Common Shares 2021-03-23 4 S 0 12000 126.97 D 1050 D Stock Option (Right to Buy) 14.43 2021-03-23 4 M 0 12000 0.00 D 2027-06-14 Common Shares 12000 2666 D Stock Option (Right to Buy) 17.66 2021-03-23 4 M 0 12000 0.00 D 2027-11-14 Common Shares 12000 3000 D Stock Option (Right to Buy) 51.49 2021-03-23 4 M 0 22000 0.00 D 2028-03-06 Common Shares 22000 38000 D Stock Option (Right to Buy) 29.87 2021-03-23 4 M 0 10000 0.00 D 2029-01-01 Common Shares 10000 10000 D Stock Option (Right to Buy) 40.87 2021-03-23 4 M 0 20000 0.00 D 2029-03-05 Common Shares 20000 25000 D Stock Option (Right to Buy) 44.67 2021-03-23 4 M 0 12000 0.00 D 2030-03-10 Common Shares 12000 43000 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $124.78 to $132.255, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $124.80 to $130.015, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range. 100% of the shares shall vest in 48 equal monthly installments on the fifteenth day of each month, with the first vesting event on July 15, 2017. 100% of the shares shall vest in 48 equal monthly installments on the fifteenth day of each month, with the first vesting event on December 15, 2017. 100% of the shares shall vest in 48 equal monthly installments on the seventh day of each month, with the first vesting event on April 7, 2018. 25% of the option shall vest on January 2, 2020, and the remaining 75% of the shares shall vest in 36 equal monthly installments on the final day of each month. This option was granted on March 5, 2019 with respect to 45,000 Common Shares. 100% of the shares will vest in 48 equal monthly installments, with the first vesting date of April 5, 2019. This option was granted on March 10, 2020 with respect to 55,000 Common Shares. 100% of the shares will vest in 48 equal monthly installments, with the first vesting date of April 10, 2020. /s/ Michael Esposito, attorney-in-fact 2021-03-25