X0206 3 2018-06-20 0 0001690585 Magenta Therapeutics, Inc. MGTA 0001219016 BONNEY MICHAEL W C/O MAGENTA THERAPEUTICS, INC. 50 HAMPSHIRE STREET CAMBRIDGE MA 02139 1 0 0 0 Common Stock 193499 D Series A Preferred Stock Common Stock 19359 D Series B Preferred Stock Common Stock 2488 D Each share of Series A Preferred Stock is convertible into shares of the Issuer's common stock, $0.001 par value per share ("Common Stock"), on a 2.58398:1 basis. Upon the closing of the Issuer's initial public offering, all shares of Series A Preferred Stock will convert into shares of Common Stock of the Issuer. The Series A Preferred Stock has no expiration date. Each share of Series B Preferred Stock is convertible into shares of the Issuer's Common Stock on a 2.58398:1 basis. Upon the closing of the Issuer's initial public offering, all shares of Series B Preferred Stock will convert into shares of Common Stock of the Issuer. The Series B Preferred Stock has no expiration date. Exhibit 24.1: Power of Attorney /s/ Zoran Zdraveski, Attorney-in-Fact for Michael W. Bonney 2018-06-20