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The RSUs vest in four equal annual installments beginning on August 26, 2022, subject to the Reporting Person's continued service through the applicable vesting date."}],"balance_after":26567,"source":{"system":"sec-edgar","filing":"0000899243-21-034499","document":"doc4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000089924321034499/doc4.xml","form_type":"4"}},{"id":2881985,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":67253,"kind":"person","name":"Keutzer Timothy","position":1,"cik":"0001798155","reported_name":"Keutzer Timothy","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Development Officer"}}],"security":"Stock Option (Right to Buy)","published_at":"2021-02-04T00:52:13.000Z","date":"2021-02-01","kind":"grant","acquired":true,"shares":57432,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"The shares underlying this option vest as to 25% on February 1, 2022, with the remainder vesting in 36 equal monthly installments thereafter, subject to the Reporting Person's continued service through the applicable vesting date."}],"balance_after":57432,"derivative":{"exercise_price":19.18,"expiration_date":"2031-02-01","underlying":"Common Stock","underlying_shares":57432},"source":{"system":"sec-edgar","filing":"0000899243-21-004790","document":"doc4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000089924321004790/doc4.xml","form_type":"4"}},{"id":3294969,"issuer":{"id":7014,"kind":"organization","name":"Spero Therapeutics, Inc."},"owners":[{"id":67253,"kind":"person","name":"Keutzer Timothy","position":1,"cik":"0001798155","reported_name":"Keutzer Timothy","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Development Officer"}}],"security":"Stock Option (Right to Buy)","published_at":"2020-02-03T22:28:26.000Z","date":"2020-02-03","kind":"grant","acquired":true,"shares":55000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"The shares underlying this option vest as to 25% on February 3, 2021, with the remainder vesting in 36 equal monthly installments thereafter, subject to the Reporting Person's continued service through the applicable vesting date."}],"balance_after":55000,"derivative":{"exercise_price":9.34,"expiration_date":"2030-02-03","underlying":"Common Stock","underlying_shares":55000},"source":{"system":"sec-edgar","filing":"0000899243-20-002604","document":"doc4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1701108/000089924320002604/doc4.xml","form_type":"4"}}]}