X0306 4 2020-06-17 0 0001564824 Allakos Inc. ALLK 0001198330 NOHRA GUY P ONE EMBARCADERO CENTER SUITE 3700 SAN FRANCISCO CA 94111 0 0 1 0 Common Stock 2020-06-17 4 S 0 5672 75.23 D 2020 D Common Stock 2020-06-17 4 S 0 1414 76.52 D 606 D Common Stock 2020-06-17 4 S 0 606 77.21 D 0 D Common Stock 7961823 I See Footnote The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $75.00 - $75.89, 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 set forth in this footnote to this Form 4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $76.11 - $77.095, 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 set forth in this footnote to this Form 4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $77.15 - $77.31, 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 set forth in this footnote to this Form 4. These shares are directly held by Alta VIII, L.P. ("Alta VIII"). Alta Partners Management VIII, LLC ("Alta Management VIII") is the general partner of Alta VIII. The Reporting Person is one of three managing directors of Alta Management VIII and, as such, may be deemed to share voting and investment control with respect to the shares held by Alta VIII. The Reporting Person disclaims beneficial ownership of all shares held by Alta VIII, except to the extent of his pecuniary interest therein. /s/ Guy P. Nohra 2020-06-19