{"transactions":[{"id":2151278,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-09-26T19:32:06.000Z","date":"2022-09-22","kind":"sale","acquired":false,"shares":566284,"price":2.2503,"value":1274308.8852,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"Aquilo Capital, LP owns only 2,176,470 of the 3,419,435 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not sell any of the 566,284 shares sold in this transaction on 09/22/2022."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":3419435,"source":{"system":"sec-edgar","filing":"0001591986-22-000018","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198622000018/primary_doc.xml","form_type":"4"}},{"id":2151277,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-09-26T19:32:06.000Z","date":"2022-09-22","kind":"sale","acquired":false,"shares":1335512,"price":2.2503,"value":3005302.6536,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP owns 2,176,470 of the 3,985,719 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP sold 1,335,512 shares in this transaction on 09/22/2022."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":3985719,"source":{"system":"sec-edgar","filing":"0001591986-22-000018","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198622000018/primary_doc.xml","form_type":"4"}},{"id":2288768,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-04-28T20:13:08.000Z","date":"2022-04-26","kind":"purchase","acquired":true,"shares":39727,"price":5.235,"value":207970.845,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP only owns 3,511,982 of the 5,321,231 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP purchased 39,727 shares in this transaction on 4/26/2022."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":5321231,"source":{"system":"sec-edgar","filing":"0001591986-22-000015","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198622000015/primary_doc.xml","form_type":"4"}},{"id":2312972,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-03-31T19:51:52.000Z","date":"2022-03-30","kind":"purchase","acquired":true,"shares":16885,"price":8.7884,"value":148392.134,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"Aquilo Capital, LP only owns 3,472,255 of the 5,281,504 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 16,885 shares purchased in this transaction on 03/30/2022."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":5281504,"source":{"system":"sec-edgar","filing":"0001591986-22-000014","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198622000014/primary_doc.xml","form_type":"4"}},{"id":2312971,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-03-31T19:51:52.000Z","date":"2022-03-30","kind":"purchase","acquired":true,"shares":33115,"price":8.7884,"value":291027.866,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP only owns 3,472,255 of the 5,264,619 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP purchased 33,115 shares in this transaction on 3/30/2022."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":5264619,"source":{"system":"sec-edgar","filing":"0001591986-22-000014","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198622000014/primary_doc.xml","form_type":"4"}},{"id":2330817,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-03-16T20:23:03.000Z","date":"2022-03-14","kind":"purchase","acquired":true,"shares":8006,"price":7.626,"value":61053.756,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"Aquilo Capital, LP only owns  3,439,140 of the 5,231,504 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 8,006 shares purchased in this transaction on 03/14/2022."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":5231504,"source":{"system":"sec-edgar","filing":"0001591986-22-000013","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198622000013/primary_doc.xml","form_type":"4"}},{"id":2330816,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-03-16T20:23:03.000Z","date":"2022-03-14","kind":"purchase","acquired":true,"shares":15702,"price":7.626,"value":119743.452,"ownership":{"direct":false,"nature":"See footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP only owns 3,439,140 of the 5,223,498 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP purchased 15,702 shares in this transaction on 3/14/2022."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":5223498,"source":{"system":"sec-edgar","filing":"0001591986-22-000013","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198622000013/primary_doc.xml","form_type":"4"}},{"id":2360900,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-03-02T20:52:46.000Z","date":"2022-02-28","kind":"purchase","acquired":true,"shares":15104,"price":9.5293,"value":143930.5472,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"Aquilo Capital, LP owns only 3,423,438 of the 5,207,796 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 15,104 shares purchased in this transaction on 02/28/2022."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":5207796,"source":{"system":"sec-edgar","filing":"0001591986-22-000011","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198622000011/primary_doc.xml","form_type":"4"}},{"id":2360899,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-03-02T20:52:46.000Z","date":"2022-02-28","kind":"purchase","acquired":true,"shares":29729,"price":9.5293,"value":283296.5597,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP owns 3,423,438 of the 5,192,692 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP purchased 29,729 shares in this transaction on 2/28/2022."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":5192692,"source":{"system":"sec-edgar","filing":"0001591986-22-000011","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198622000011/primary_doc.xml","form_type":"4"}},{"id":2378700,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-02-23T21:24:26.000Z","date":"2022-02-18","kind":"purchase","acquired":true,"shares":14828,"price":9.2419,"value":137038.8932,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP owns 3,393,709 of the 5,162,963 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP purchased 14,828 shares in this transaction on 2/18/2022."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":5162963,"source":{"system":"sec-edgar","filing":"0001591986-22-000010","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198622000010/primary_doc.xml","form_type":"4"}},{"id":2419314,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-02-02T01:26:17.000Z","date":"2022-01-31","kind":"purchase","acquired":true,"shares":125000,"price":11.5861,"value":1448262.5,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP owns only 3,378,881 of the 5,148,135 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 125,000 shares purchased in this transaction on 01/31/2022."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":5148135,"source":{"system":"sec-edgar","filing":"0001591986-22-000004","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198622000004/primary_doc.xml","form_type":"4"}},{"id":2425231,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-01-26T22:12:06.000Z","date":"2022-01-24","kind":"purchase","acquired":true,"shares":1599,"price":10.8931,"value":17418.0669,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP owns only 3,378,881 of the 5,023,135 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 1,599 shares purchased in this transaction on 01/24/2022."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":5023135,"source":{"system":"sec-edgar","filing":"0001591986-22-000003","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198622000003/primary_doc.xml","form_type":"4"}},{"id":2430632,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-01-20T18:07:05.000Z","date":"2022-01-18","kind":"purchase","acquired":true,"shares":48488,"price":12.4147,"value":601963.9736,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP owns only 3,378,881 of the 5,021,536 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 48,488 shares purchased in this transaction on 01/18/2022."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":5021536,"source":{"system":"sec-edgar","filing":"0001591986-22-000002","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198622000002/primary_doc.xml","form_type":"4"}},{"id":2436855,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-01-12T21:43:28.000Z","date":"2022-01-10","kind":"purchase","acquired":true,"shares":8867,"price":12.9253,"value":114608.6351,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP owns only 3,378,881 of the 4,973,048 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 8,867 shares purchased in this transaction on 01/10/2022."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4973048,"source":{"system":"sec-edgar","filing":"0001591986-22-000001","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198622000001/primary_doc.xml","form_type":"4"}},{"id":2454388,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-01-03T19:46:29.000Z","date":"2021-12-31","kind":"purchase","acquired":true,"shares":125000,"price":15.7522,"value":1969025.0,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"Aquilo Capital, LP owns only 3,378,881 of the 4,964,181 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 125,000 shares purchased in this transaction on 12/31/2021."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4964181,"source":{"system":"sec-edgar","filing":"0001691902-22-000001","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000169190222000001/primary_doc.xml","form_type":"4"}},{"id":2454387,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-01-03T19:46:29.000Z","date":"2021-12-30","kind":"purchase","acquired":true,"shares":50000,"price":15.7722,"value":788610.0,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"Aquilo Capital, LP owns only 3,378,881 of the 4,839,181 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 50,000 shares purchased in this transaction on 12/30/2021."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4839181,"source":{"system":"sec-edgar","filing":"0001691902-22-000001","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000169190222000001/primary_doc.xml","form_type":"4"}},{"id":2454386,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2022-01-03T19:46:29.000Z","date":"2021-12-29","kind":"purchase","acquired":true,"shares":75493,"price":14.6406,"value":1105262.8158,"ownership":{"direct":false,"nature":"See footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP owns only 3,378,881 of the 4,789,181 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 75,493 shares purchased in this transaction on 12/29/2021."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4789181,"source":{"system":"sec-edgar","filing":"0001691902-22-000001","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000169190222000001/primary_doc.xml","form_type":"4"}},{"id":2528987,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2021-11-02T21:47:57.000Z","date":"2021-10-29","kind":"purchase","acquired":true,"shares":150000,"price":17.5345,"value":2630175.0,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP owns only 3,378,881 of the 4,713,688 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 150,000 shares purchased in this transaction on 10/29/2021."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4713688,"source":{"system":"sec-edgar","filing":"0001591986-21-000016","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000016/primary_doc.xml","form_type":"4"}},{"id":2552122,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2021-10-04T15:36:44.000Z","date":"2021-09-30","kind":"purchase","acquired":true,"shares":134543,"price":18.6496,"value":2509173.1328,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"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."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4563688,"source":{"system":"sec-edgar","filing":"0001591986-21-000015","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000015/primary_doc.xml","form_type":"4"}},{"id":2569384,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2021-09-15T23:21:42.000Z","date":"2021-09-14","kind":"purchase","acquired":true,"shares":2156,"price":18.4937,"value":39872.4172,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"Aquilo Capital, LP owns only 3,378,881 of the 4,429,145 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 2,156 shares purchased in this transaction on 09/14/2021."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4429145,"source":{"system":"sec-edgar","filing":"0001591986-21-000014","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000014/primary_doc.xml","form_type":"4"}},{"id":2569383,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2021-09-15T23:21:42.000Z","date":"2021-09-13","kind":"purchase","acquired":true,"shares":44210,"price":18.5631,"value":820674.651,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP owns only 3,378,881 of the  4,426,989 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 44,210 shares purchased in this transaction on 09/13/2021."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4426989,"source":{"system":"sec-edgar","filing":"0001591986-21-000014","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000014/primary_doc.xml","form_type":"4"}},{"id":2573257,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2021-09-10T21:21:53.000Z","date":"2021-09-09","kind":"purchase","acquired":true,"shares":24749,"price":18.4974,"value":457792.1526,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP owns only 3,378,881 of the 4,382,779 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 24,749 shares purchased in this transaction on 09/09/2021."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4382779,"source":{"system":"sec-edgar","filing":"0001591986-21-000013","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000013/primary_doc.xml","form_type":"4"}},{"id":2583623,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2021-09-01T21:42:57.000Z","date":"2021-08-31","kind":"purchase","acquired":true,"shares":48645,"price":18.9261,"value":920660.1345,"ownership":{"direct":false,"nature":"See Footnotes."},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"Aquilo Capital, LP owns only 3,378,881 of the 4,358,030 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 48,645 shares purchased in this transaction on 08/31/2021."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4358030,"source":{"system":"sec-edgar","filing":"0001591986-21-000012","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000012/primary_doc.xml","form_type":"4"}},{"id":2583622,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2021-09-01T21:42:57.000Z","date":"2021-08-30","kind":"purchase","acquired":true,"shares":44042,"price":17.8661,"value":786858.7762,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP owns only 3,378,881 of the 4,309,385 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 44,042 shares purchased in this transaction on 08/30/2021."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4309385,"source":{"system":"sec-edgar","filing":"0001591986-21-000012","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000012/primary_doc.xml","form_type":"4"}},{"id":2588209,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2021-08-27T21:11:07.000Z","date":"2021-08-27","kind":"purchase","acquired":true,"shares":13957,"price":16.8755,"value":235531.3535,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"Aquilo Capital, LP owns only 3,378,881 of the 4,265,343 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 13,957 shares purchased in this transaction on 08/27/2021."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4265343,"source":{"system":"sec-edgar","filing":"0001591986-21-000011","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000011/primary_doc.xml","form_type":"4"}},{"id":2588208,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2021-08-27T21:11:07.000Z","date":"2021-08-26","kind":"purchase","acquired":true,"shares":22982,"price":16.5487,"value":380322.2234,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP owns only 3,378,881 of the 4,251,386 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 22,982 shares purchased in this transaction on 08/26/2021."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4251386,"source":{"system":"sec-edgar","filing":"0001591986-21-000011","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000011/primary_doc.xml","form_type":"4"}},{"id":2592367,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2021-08-24T20:28:00.000Z","date":"2021-08-24","kind":"purchase","acquired":true,"shares":40170,"price":16.2757,"value":653794.869,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"Aquilo Capital, LP owns only 3,378,881 of the 4,228,404 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 40,170 shares purchased in this transaction on 08/24/2021."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4228404,"source":{"system":"sec-edgar","filing":"0001591986-21-000010","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000010/primary_doc.xml","form_type":"4"}},{"id":2592366,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2021-08-24T20:28:00.000Z","date":"2021-08-23","kind":"purchase","acquired":true,"shares":137835,"price":16.3336,"value":2251341.756,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"Aquilo Capital, LP owns only 3,378,881 of the 4,188,234 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 137,835 shares purchased in this transaction on 08/23/2021."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4188234,"source":{"system":"sec-edgar","filing":"0001591986-21-000010","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000010/primary_doc.xml","form_type":"4"}},{"id":2592365,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2021-08-24T20:28:00.000Z","date":"2021-08-20","kind":"purchase","acquired":true,"shares":221190,"price":14.8601,"value":3286905.519,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Aquilo Capital, LP owns only 3,378,881 of the 4,050,399 shares deemed to be beneficially owned by Aquilo Capital Management, LLC. Aquilo Capital, LP did not purchase any of the 221,190 shares purchased in this transaction on 08/20/2021."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4050399,"source":{"system":"sec-edgar","filing":"0001591986-21-000010","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000010/primary_doc.xml","form_type":"4"}},{"id":2869286,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 Par Value","published_at":"2021-02-10T18:35:13.000Z","date":"2021-02-08","kind":"sale","acquired":false,"shares":3000,"price":21.7384,"value":65215.2,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":3829209,"source":{"system":"sec-edgar","filing":"0001591986-21-000003","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000003/primary_doc.xml","form_type":"4"}},{"id":2879241,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 Par Value","published_at":"2021-02-04T23:46:54.000Z","date":"2021-02-04","kind":"sale","acquired":false,"shares":34144,"price":18.9859,"value":648254.5696,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":3832209,"source":{"system":"sec-edgar","filing":"0001591986-21-000001","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000001/primary_doc.xml","form_type":"4"}},{"id":2879240,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 Par Value","published_at":"2021-02-04T23:46:54.000Z","date":"2021-02-03","kind":"sale","acquired":false,"shares":29354,"price":18.9787,"value":557100.7598,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":3866353,"source":{"system":"sec-edgar","filing":"0001591986-21-000001","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000001/primary_doc.xml","form_type":"4"}},{"id":2879239,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 Par Value","published_at":"2021-02-04T23:46:54.000Z","date":"2021-02-02","kind":"sale","acquired":false,"shares":22841,"price":18.9909,"value":433771.1469,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":3895707,"source":{"system":"sec-edgar","filing":"0001591986-21-000001","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000001/primary_doc.xml","form_type":"4"}},{"id":2879238,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 Par Value","published_at":"2021-02-04T23:46:54.000Z","date":"2021-02-01","kind":"sale","acquired":false,"shares":13661,"price":19.2417,"value":262860.8637,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":3918548,"source":{"system":"sec-edgar","filing":"0001591986-21-000001","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198621000001/primary_doc.xml","form_type":"4"}},{"id":2938037,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2020-12-18T21:43:14.000Z","date":"2020-12-17","kind":"sale","acquired":false,"shares":250000,"price":18.8129,"value":4703225.0,"ownership":{"direct":false,"nature":"See footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":3932209,"source":{"system":"sec-edgar","filing":"0001591986-20-000019","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198620000019/primary_doc.xml","form_type":"4"}},{"id":2938036,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2020-12-18T21:43:14.000Z","date":"2020-12-16","kind":"sale","acquired":false,"shares":14933,"price":18.6188,"value":278034.5404,"ownership":{"direct":false,"nature":"See footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4182209,"source":{"system":"sec-edgar","filing":"0001591986-20-000019","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198620000019/primary_doc.xml","form_type":"4"}},{"id":2986646,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2020-11-11T00:14:26.000Z","date":"2020-11-09","kind":"sale","acquired":false,"shares":125900,"price":13.7734,"value":1734071.06,"ownership":{"direct":false,"nature":"See footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4197142,"source":{"system":"sec-edgar","filing":"0001591986-20-000016","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198620000016/primary_doc.xml","form_type":"4"}},{"id":2989796,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2020-11-07T01:48:12.000Z","date":"2020-11-06","kind":"sale","acquired":false,"shares":5000,"price":13.7747,"value":68873.5,"ownership":{"direct":false,"nature":"See footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4323042,"source":{"system":"sec-edgar","filing":"0001591986-20-000015","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198620000015/primary_doc.xml","form_type":"4"}},{"id":2989795,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2020-11-07T01:48:12.000Z","date":"2020-11-05","kind":"sale","acquired":false,"shares":96600,"price":13.9786,"value":1350332.76,"ownership":{"direct":false,"nature":"See footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4328042,"source":{"system":"sec-edgar","filing":"0001591986-20-000015","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198620000015/primary_doc.xml","form_type":"4"}},{"id":2989794,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":123547,"kind":"organization","name":"Aquilo Capital, L.P.","position":2,"cik":"0001491371","reported_name":"Aquilo Capital, L.P.","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2020-11-07T01:48:12.000Z","date":"2020-11-04","kind":"sale","acquired":false,"shares":72500,"price":14.2585,"value":1033741.25,"ownership":{"direct":false,"nature":"See footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"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."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"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."}],"balance_after":4424642,"source":{"system":"sec-edgar","filing":"0001591986-20-000015","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000159198620000015/primary_doc.xml","form_type":"4"}},{"id":3077551,"issuer":{"id":4452,"kind":"organization","name":"PALVELLA THERAPEUTICS, INC.","symbol":"PVLA"},"owners":[{"id":103917,"kind":"organization","name":"Aquilo Capital Management, LLC","position":1,"cik":"0001591986","reported_name":"Aquilo Capital Management, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock, $0.001 par value","published_at":"2020-07-22T22:15:47.000Z","date":"2020-07-21","kind":"sale","acquired":false,"shares":1900000,"price":2.95,"value":5605000.0,"ownership":{"direct":false,"nature":"See footnotes"},"footnotes":[{"field":"security","element":"securityTitle","label":"F1","text":"The reporting persons are Aquilo Capital Management, LLC (\"Aquilo\") and Marc R. Schneidman. Aquilo is the general partner and investment adviser of investment funds that hold these 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 those funds, and Mr. Schneidman may be deemed to beneficially own them indirectly as the control person of Aquilo. Each of Aquilo and Mr. Schneidman disclaims beneficial ownership of such securities except to the extent of his or its pecuniary interest therein."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"The reporting persons are Aquilo Capital Management, LLC (\"Aquilo\") and Marc R. Schneidman. Aquilo is the general partner and investment adviser of investment funds that hold these 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 those funds, and Mr. Schneidman may be deemed to beneficially own them indirectly as the control person of Aquilo. Each of Aquilo and Mr. Schneidman disclaims beneficial ownership of such securities except to the extent of his or its pecuniary interest therein."}],"balance_after":3675530,"source":{"system":"sec-edgar","filing":"0001591986-20-000011","document":"primary_doc.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1583648/000159198620000011/primary_doc.xml","form_type":"4"}}]}