Spero Therapeutics, Inc. (SPRO) Insider Trading & SEC Filings

Updated Jul 16, 2026 · Last SEC filing 2026-06-25

Spero Therapeutics, Inc. (SPRO) has filed 8 SEC Form 4 insider transactions in the last 90 days, with the most recent on 2026-06-25. 4 Form 8-K material event filings were reported by SPRO in the last 90 days. InsiderAlpha tracks every SPRO SEC filing — Form 4, Form 144, and 8-K — in real time, including Rule 10b5-1 plan detection.

About Spero Therapeutics, Inc. (SPRO)

SEC CIK0001701108

90-Day SEC Filing Activity

Form 4 filings (90d)8
Form 8-K filings (90d)4
Latest Form 4 filing2026-06-25

Recent SPRO Insider Transactions (Form 4)

DateInsiderRoleTransactionSharesPriceValueFiling
Jackson Scott ThomasInsiderA — Grant or award10.0K$0.00—SEC
Smith CynthiaInsiderA — Grant or award10.0K$0.00—SEC
Tregoning KathleenInsiderA — Grant or award10.0K$0.00—SEC
Deshpande MilindInsiderA — Grant or award10.0K$0.00—SEC
THOMAS FRANK EInsiderA — Grant or award10.0K$0.00—SEC
VINK PATRICK V.J.J.InsiderA — Grant or award10.0K$0.00—SEC
Pottage John C JrInsiderA — Grant or award10.0K$0.00—SEC
Rajavelu EstherSee RemarksS — Open-market sale25.2K$2.51$63KSEC
Rajavelu EstherSee RemarksS — Open-market sale50.8K$2.36$120KSEC
Keutzer TimothyChief Operating OfficerS — Open-market sale18.7K$2.36$44KSEC
Rajavelu EstherSee RemarksS — Open-market sale37.1K$2.36$88KSEC
Keutzer TimothyChief Operating OfficerS — Open-market sale3.5K$2.24$8KSEC
Keutzer TimothyChief Operating OfficerS — Open-market sale24.2K$2.14$52KSEC
Keutzer TimothyChief Operating OfficerS — Open-market sale18.9K$2.20$42KSEC
Keutzer TimothyChief Operating OfficerA — Grant or award68.0K$0.00—SEC

All transactions sourced from SEC EDGAR Form 4 filings for Spero Therapeutics, Inc. (SPRO). Updated in real time as new filings are submitted to the SEC.

Most-Active SPRO Insiders — Last 90 Days

InsiderForm 4 filingsTotal transaction value
Deshpande Milind2—
Jackson Scott Thomas2—
THOMAS FRANK E2—
Smith Cynthia2—
Tregoning Kathleen2—

Recent SPRO Form 8-K Material Events

Recent Insider Filings

Form 4 Transaction Code Reference

SEC Form 4 transactions are reported with a one-letter code indicating the type of transaction. Common codes you'll see in SPRO insider filings:

POpen-market purchase by the insider
SOpen-market sale by the insider
AGrant, award, or other acquisition from the issuer
MExercise or conversion of derivative security (e.g. options)
FPayment of exercise price or tax liability via share withholding
GBona-fide gift of securities
DDisposition to the issuer (e.g. share buyback participation)
JOther acquisition or disposition
XExercise of in-the-money or at-the-money derivative security
CConversion of derivative security
VTransaction voluntarily reported earlier than required

SPRO Insider Trading — FAQ

What is the latest insider trade for SPRO?
Spero Therapeutics, Inc. (SPRO) had 8 insider filings in the last 90 days, with the most recent on 2026-06-25. InsiderAlpha tracks every Form 4, 10-K, 10-Q, and 8-K filing in real time.
How many insiders are buying SPRO stock?
0 insider purchases of SPRO were filed in the last 90 days.
How many insiders are selling SPRO stock?
0 insider sales of SPRO were filed in the last 90 days.
Where can I see SPRO SEC filings (Form 4, 10-K, 10-Q, 8-K)?
InsiderAlpha aggregates every SPRO SEC filing — Form 4 insider transactions, 10-K and 10-Q quarterly reports, and 8-K material event disclosures — in one timeline.

Learn More

Open the live SPRO dashboard on InsiderAlpha for real-time alerts, charting, and full historical filing search.