X0306 4 2020-05-26 0 0001383701 Histogen Inc. HSTO 0001297506 Naughton Gail K C/O HISTOGEN INC. 10655 SORRENTO VALLEY RD., STE 200 SAN DIEGO CA 92121 0 1 0 0 See Remarks Common Stock 2020-05-26 4 J 0 426526 0.00 A 426526 I See Footnote Stock Option (right to buy) 0.53 2012-05-12 4 J 0 380063 0.00 A 2022-05-12 Common Stock 380063 380063 D Shares of common stock of the corporation formerly known as Histogen Inc. ("Histogen") were converted into shares of common stock of the Issuer pursuant to that certain Agreement and Plan of Merger and Reorganization, dated as of January 28, 2020, by and among the Issuer, Chinook Merger Sub, Inc. and Histogen (the "Merger Agreement"). Pursuant to the terms of the Merger Agreement, each share of Histogen common stock was exchanged for 1.4342 shares of the Issuer's common stock (the "Conversion"). Immediately following the merger, the Issuer changed its name to Histogen Inc. All share numbers reflect the one-for-ten reverse stock split (the "Reverse Split") effected by the Issuer immediately prior to the completion of the merger. Shares held by the Gail K. Naughton Revocable Trust, dated January 19, 2018. Fully vested. Shares subject to the option and the exercise price have been adjusted based upon the Conversion and Reverse Split. Founder, Chief Scientific Officer & Chief Business Development Officer /s/ Richard W. Pascoe as attorney-in-fact for Gail K. Naughton 2020-05-28