X0306 4 2021-12-10 0 0001711279 Krystal Biotech, Inc. KRYS 0001298711 Krishnan Suma C/O KRYSTAL BIOTECH, INC. 2100 WHARTON STREET, SUITE 701 PITTSBURGH PA 15203 1 1 1 0 Chief Operating Officer Common Stock 2021-12-10 4 S 0 100000 70.50 D 50000 I By trust Common Stock 1798226 D Common Stock 1848624 I By spouse On December 3, 2021, Krystal Biotech, Inc. (the "Company"), closed the previously announced underwritten public offering of 2,666,667 shares of its common stock, at a public offering price of $75.00 per share. The Company and certain selling stockholders granted the underwriters a 30-day option to purchase up to an additional 400,000 shares of the Company's common stock offered in the public offering, which includes up to 200,000 shares from the selling stockholders. The underwriters exercised the option and on December 10, 2021, purchased the 400,000 shares of the Company's common stock, including 100,000 shares of the Company's common stock from the Krishnan Family Trust, a selling stockholder. Directly beneficially owned by the Krishnan Family Trust. The reporting person and her spouse are each joint beneficial owners of the trust with joint voting and investment control. Prior to the reported transaction, the Krishnan Family Trust held 112,162 shares. In connection with the reported transaction, 18,919 shares were transferred to the Krishnan Family Trust from the reporting person's individual account and 18,919 shares were transferred to the Krishnan Family Trust from Krish Krishnan's, the reporting person's spouse, individual account. Directly beneficially owned by Krish Krishnan, the spouse of the reporting person. /s/ Suma Krishnan 2021-12-14