X0306 4 2020-01-10 false 0001690585 Magenta Therapeutics, Inc. MGTA 0001741286 GARDNER JASON C/O MAGENTA THERAPEUTICS, INC. 100 TECHNOLOGY SQUARE CAMBRIDGE MA 02139 true true false false See Remarks Common Stock 2020-01-10 4 S false 11200.00 15.25 D 251212.00 D Common Stock 292990.00 I By J.P. Gardner Irrevocable Trust Common Stock 359092.00 I By P.S. Gardner Irrevocable Trust This trade is pursuant to an active 10b5-1 plan. This transaction was executed in multiple trades at prices ranging from $15.10 to $15.58. The price reported above reflects the weighted average price. The reporting person hereby undertakes to provide upon request by the staff of the U.S. Securities and Exchange Commission, the issuer or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected. President and Chief Executive Officer /s/ Zoran Zdraveski, Attorney-in- Fact for Jason Gardner 2020-01-10