SEC Form 4 · accession 0000899243-17-025510

Spero Therapeutics, Inc. · SPRO

Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗

Reporting owner

Director

Period of report

Nov 6, 2017

Accepted (ET)

Nov 7, 2017 · 4:08 pm EST

Rule 10b5-1 plan

unknown — predates the checkbox

Issuer CIK

0001701108

Table I — non-derivative securities

Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Common Stock^F2,F3	Nov 6, 2017	C	245,605	—	A	288,386	I	See Footnote
Common Stock^F2,F3	Nov 6, 2017	C	246,272	—	A	534,658	I	See Footnote
Common Stock^F2,F3	Nov 6, 2017	C	328,992	—	A	863,650	I	See Footnote
Common Stock^F2,F3	Nov 6, 2017	C	513,318	—	A	1,376,968	I	See Footnote
Common Stock^F2,F4	Nov 6, 2017	C	602,589	—	A	1,979,557	I	See Footnote
Common Stock^F1,F4	Nov 6, 2017	P	428,571	$14.00	A	2,408,128	I	See Footnote

Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	D/I
Junior Preferred Stock^F3,F2	—	Nov 6, 2017	C	1,492,645	D	—	—	Common Stock	245,605	I
Series A Preferred Stock^F3,F2	—	Nov 6, 2017	C	982,906	D	—	—	Common Stock	246,272	I
Series B Preferred Stock^F3,F2	—	Nov 6, 2017	C	1,250,000	D	—	—	Common Stock	328,992	I
Series C Preferred Stock^F3,F2	—	Nov 6, 2017	C	3,119,633	D	—	—	Common Stock	513,318	I
Series C Preferred Stock^F4,F2	—	Nov 6, 2017	C	3,662,178	D	—	—	Common Stock	602,589	I

F1Reflects shares of the Issuer's common stock that were purchased in connection with the Issuer's initial public offering.
F2Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.
F3Shares held by Atlas Venture Fund IX, L.P. ("Atlas Venture Fund IX"). The general partner of Atlas Venture Fund IX is Atlas Venture Associates IX, L.P. ("AVA IX LP"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.
F4Shares held by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. Dr. Formela is a member of AVA X LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.