X0206 3 2020-10-22 0 0001822462 Foghorn Therapeutics Inc. FHTX 0001362558 Abu Dhabi Investment Authority 211 CORNICHE STREET PO BOX 3600 ABU DHABI C0 0000 UNITED ARAB EMIRATES true 0001790748 Platinum International Investment Holding RSC Ltd 26TH FLOOR, AL KHATEM TOWER, ADGM SQUARE PO BOX 25642, AL MARYAH ISLAND ABU DHABI C0 NA UNITED ARAB EMIRATES true 0001790749 Platinum Falcon B 2018 RSC Ltd 26TH FLOOR, AL KHATEM TOWER, ADGM SQUARE PO BOX 25642, AL MARYAH ISLAND ABU DHABI C0 NA UNITED ARAB EMIRATES true Series B Preferred Stock Common Stock 1081081 D The Series B Preferred Stock is convertible (i) at any time at the option of the holder; (ii) automatically upon the closing of the sale of shares of Common Stock of the Issuer to the public in a firm-commitment underwritten public offering pursuant to an effective registration statement under the Securities Act of 1933, as amended, resulting in at least $35,000,000 of gross proceeds to the Issuer; or (iii) at the date and time specified by, or upon the occurrence of an event specified by, the holders of a majority of the then-outstanding shares of Preferred Stock of the Issuer (calculated on an as-converted-to-Common Stock basis), voting together as a single class. Every 1.85 shares of Series B Preferred Stock is convertible into one share of Common Stock, subject to the adjustments set forth in the Second Amended and Restated Certificate of Incorporation of the Issuer. Platinum Falcon B 2018 RSC Limited ("Platinum Falcon") directly holds the Series B Preferred Stock. Platinum International Investment Holding RSC Limited ("Platinum Holdings") is the sole owner of Platinum Falcon, and the Abu Dhabi Investment Authority ("ADIA" and, together with Platinum Falcon and Platinum Holdings, the "Reporting Persons") is the sole owner of Platinum Holdings. Therefore, Platinum Holdings and ADIA may also be deemed to beneficially own the Series B Preferred Stock. /s/ Humaid Bin Butti Bin Humaid Bin Bishr AlMarri, Authorized Signatory of Abu Dhabi Investment Authority 2020-10-22 /s/ Ahmed Mohamed Ghubash, Authorized Signatory of Abu Dhabi Investment Authority 2020-10-22 /s/ Humaid Bin Butti Bin Humaid Bin Bishr AlMarri, Authorized Signatory of Platinum International Investment Holding RSC Limited 2020-10-22 /s/ Ahmed Mohamed Ghubash, Authorized Signatory of Platinum International Investment Holding RSC Limited 2020-10-22 /s/ Humaid Bin Butti Bin Humaid Bin Bishr AlMarri, Authorized Signatory of Platinum Falcon B 2018 RSC Limited 2020-10-22 /s/ Ahmed Mohamed Ghubash, Authorized Signatory of Platinum Falcon B 2018 RSC Limited 2020-10-22