Mary Beth Dooley - 29 Oct 2025 Form 4 Insider Report for SYNLOGIC, INC. (SYBX)

Reporting relationship: Principal Executive Officer and Principal Financial Officer
Issuer ticker: SYBX
Reported as of: 29 Oct 2025
Net transaction value: -$284
SEC form: 4
Accepted by SEC: 31 Oct 2025, 15:30:03 UTC
Prior SEC filing: 03 Apr 2025
Source filing: View source filing
Reporting owner signature: /s/ Mary Beth Dooley

Key filing fact

Mary Beth Dooley filed Form 4 for SYNLOGIC, INC. (SYBX) on 31 Oct 2025.

Key facts

This page summarizes Mary Beth Dooley's Form 4 filing for SYNLOGIC, INC. (SYBX).
1 reported transaction and 0 derivative rows are listed below.
Accepted by SEC: 31 Oct 2025, 15:30.

Change

Previous filing in this sequence was filed on 03 Apr 2025.
Current net transaction value: -$284.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0002015112 Primary reporting owner

Dooley Mary Beth

Relationship: Principal Executive Officer and Principal Financial Officer
Address: C/O SYNLOGIC, INC., PO BOX 30, WINCHESTER
Signature: /s/ Mary Beth Dooley
Signature date: 31 Oct 2025

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

SYBX transaction

Common Stock

Sale

Transaction value: $284
Shares: -157
Change %: -1.2%
Price: $1.81
Shares after: 12,744
Date: 29 Oct 2025
Ownership: Direct
Footnotes: F1

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 1 footnote

Footnote F1

Represents the number of shares sold by the reporting person on October 29, 2025 to cover the tax liability in connection with the vesting of a restricted stock award, vesting on October 28, 2025, that was granted in 2022.

SEC remarks

Principal Executive Officer and Principal Financial Officer