Spero Therapeutics, Inc. — Director's Dealing 2017

Nov 1, 2017

SEC Form 3 — Initial Statement of Beneficial Ownership

Issuer: Spero Therapeutics, Inc. (SPRO)
CIK: 0001701108
Period of Report: 2017-11-01

Reporting Person: Lundbeckfond Invest A/S (10% Owner)

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Series A Preferred Stock	$		Common Stock (289102)		Direct
Series B Preferred Stock	$		Common Stock (179450)		Direct
Series C Preferred Stock	$		Common Stock (408937)		Direct

Footnotes

F1: The shares of Series A preferred stock are convertible into the number of shares of common stock shown in Column 3, calculated using the conversion ratio set forth in the Issuer's Amended and Restated Certificate of Incorporation, as amended, at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares have no expiration date.

F2: Share numbers give effect to the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017.

F3: The shares of Series B preferred stock are convertible into the number of shares of common stock shown in Column 3, calculated using the conversion ratio set forth in the Issuer's Amended and Restated Certificate of Incorporation, as amended, at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares have no expiration date.

F4: The shares of Series C preferred stock are convertible into the number of shares of common stock shown in Column 3, calculated using the conversion ratio set forth in the Issuer's Amended and Restated Certificate of Incorporation, as amended, at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares have no expiration date.