Gossamer Bio, Inc. — Director's Dealing 2019

Feb 8, 2019

SEC Form 3 — Initial Statement of Beneficial Ownership

Issuer: Gossamer Bio, Inc. (GOSS)
CIK: 0001728117
Period of Report: 2019-02-07

Reporting Person: Burow Kristina (Director)

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Series A Preferred Stock	$0.00		Common Stock (3682539)		Indirect
Series A Preferred Stock	$0.00		Common Stock (3682539)		Indirect
Series B Preferred Stock	$0.00		Common Stock (345419)		Indirect
Series B Preferred Stock	$0.00		Common Stock (345419)		Indirect

Footnotes

F1: Each of the 16,571,429 and 16,571,428 shares of Series A Preferred Stock held by ARCH Venture Fund IX, L.P. ("ARCH IX") and ARCH Venture Fund IX Overage, L.P. ("ARCH Overage"), respectively, is convertible, at any time, at the holder's election, at a ratio of 4.5 to one share of the Issuer's common stock. In addition, effective immediately prior to the closing of the Issuer's initial public offering of its common stock, for no additional consideration, each share of Series A Preferred Stock will automatically convert at a ratio of 4.5 to one share of the Issuer's common stock. The Series A Preferred Stock has no expiration date.

F2: These shares are directly held by ARCH IX. ARCH Venture Partners IX, L.P. ("GPLP"), as the sole general partner of ARCH IX, may be deemed to beneficially own the shares held by ARCH IX. ARCH Venture Partners IX, LLC ("GPLLC"), as the sole general partner of GPLP, may be deemed to beneficially own the shares held by GPLP. The Reporting Person has an interest in the GPLP and the GPLLC but does not have voting or investment control over the shares held by ARCH IX.

F3: The Reporting Person disclaims beneficial ownership of the securities reported herein, except to the extent of her pecuniary interest therein.

F4: These shares are directly held by ARCH Overage. ARCH Venture Partners IX Overage, L.P. ("Overage GPLP"), as the sole general partner of ARCH Overage, may be deemed to beneficially own the shares held by ARCH Overage. GPLLC, as the sole general partner of Overage GPLP, may be deemed to beneficially own the shares held by Overage GPLP. The Reporting Person has an interest in the Overage GPLP and the GPLLC but does not have voting or investment control over the shares held by ARCH Overage.

F5: Each of the 1,554,388 and 1,554,388 shares of Series B Preferred Stock held by ARCH IX and ARCH Overage, respectively, is convertible, at any time, at the holder's election, at a ratio of 4.5 to one share of the Issuer's common stock. In addition, effective immediately prior to the closing of the Issuer's initial public offering of its common stock, for no additional consideration, each share of Series B Preferred Stock will automatically convert at a ratio of 4.5 to one share of the Issuer's common stock. The Series B Preferred Stock has no expiration date.