Aquilo Capital Management, LLC - Sep 30, 2021 Form 4 Insider Report for Spero Therapeutics, Inc. (SPRO)

Role: 10%+ Owner
Signature: Aquilo Capital Management, LLC By: its Managing Member, /s/ Marc Schneidman
Stock symbol: SPRO
Transactions as of: Sep 30, 2021
Transactions value $: $2,509,173
Form type: 4
Date filed: 10/4/2021, 11:36 AM
Previous filing: Sep 15, 2021
Next filing: Nov 2, 2021

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	SPRO	Common Stock, $0.001 par value	Purchase	$2.51M	+135K	+3.04%	$18.65^*	4.56M	Sep 30, 2021	See Footnotes	F1, F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The reporting persons are Aquilo Capital, L.P. (the "Fund"), Aquilo Capital Management, LLC ("Aquilo") and Marc R. Schneidman. Aquilo is the general partner and investment adviser of the Fund and other funds managed by Aquilo that hold securities directly for the benefit of their investors. Aquilo may be deemed to beneficially own such securities indirectly as the investment adviser and general partner of the Fund and affiliated funds, and Mr. Schneidman may be deemed to beneficially own them indirectly as the control person of Aquilo. Each of, Aquilo, the Fund and Mr. Schneidman disclaims beneficial ownership of such securities except to the extent of his or its pecuniary interest therein.
F2	Aquilo Capital, LP owns only 3,378,881 of the 4,563,688 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 134,543 shares purchased in this transaction on 09/30/2021.

Content

The reporting persons are Aquilo Capital, L.P. (the "Fund"), Aquilo Capital Management, LLC ("Aquilo") and Marc R. Schneidman. Aquilo is the general partner and investment adviser of the Fund and other funds managed by Aquilo that hold securities directly for the benefit of their investors. Aquilo may be deemed to beneficially own such securities indirectly as the investment adviser and general partner of the Fund and affiliated funds, and Mr. Schneidman may be deemed to beneficially own them indirectly as the control person of Aquilo. Each of, Aquilo, the Fund and Mr. Schneidman disclaims beneficial ownership of such securities except to the extent of his or its pecuniary interest therein.

Aquilo Capital, LP owns only 3,378,881 of the 4,563,688 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 134,543 shares purchased in this transaction on 09/30/2021.