Comparable stake leader
Funicular Funds, LP
SEC ownership of SYNLOGIC, INC.
Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0001527599.
Disclosed value leader
Funicular Funds, LP
Comparable rows
9/21
Latest evidence
02 Apr 2026
- Public ticker
- SYBX on OTC
- Parsed ownership sources
- 13D/G, 3/4/5, and 13F
- Largest SEC-reported holder
- Funicular Funds, LP
- Latest 13D/G holder
- Funicular Funds, LP
- Latest parsed ownership date
- 02 Apr 2026
- Issuer CIK
- 0001527599
- Issuer location
- Winchester, MA
Ownership snapshot
CIK-linked ownership evidence from parsed SEC filings.
2 signals
Issuer
Names, identifiers, and filing context for this profile.
2 identity fields
Ownership snapshot
Top shareholders of SYNLOGIC, INC. (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
Funicular Funds, LP
Disclosed value leader
Funicular Funds, LP
Comparable rows
9/21
Latest evidence
02 Apr 2026
13D/G
3/4/5
13F
Lead comparable stake: 28%
12 rows are not safely comparable across share classes.
13D/G row: Funicular Funds, LP
Showing 1-8 of 21 holder rows.
Quick read
Funicular Funds, LP leads the comparable SEC ownership view at 28%.
9 of 21 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens Funicular Funds, LP's linked filing trail.
Comparable ownership
Top 5
Funicular Funds, LP
28%
Baselake Partners, LP
9.7%
John A. Kryzanowski
6.3%
Bradley L. Radoff
4.4%
Richard P. Shea
0.13%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-8 of 21 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| Funicular Funds, LP |
13D/G
3/4/5
10%+ Owner
|
28%
|
$1,987,331
3,312,219 shares
|
$0 | 02 Apr 2026 |
| Baselake Partners, LP |
13D/G
|
9.7%
|
$1,265,400
1,140,000 shares
|
$0 | 20 Jan 2026 |
| John A. Kryzanowski |
13D/G
Kryzanowski, John A.
|
6.3%
|
$249,360
733,412 shares
|
$0 | 31 Dec 2024 |
| Bradley L. Radoff |
13D/G
Radoff Bradley Louis
|
4.4%
|
$894,400
520,000 shares
|
$0 | 30 Sep 2025 |
| Richard P. Shea |
3/4/5
Director
|
0.13%
|
$20,002
15,506 shares
|
— | 26 Apr 2025 |
| James P. Flynn |
3/4/5
Director
|
0.13%
|
$19,350
15,000 shares
|
— | 26 Apr 2025 |
| Mary Beth Dooley |
3/4/5
Principal Executive Officer and Principal Financial Officer
|
0.11%
|
$23,066
12,744 shares
|
-$284 | 29 Oct 2025 |
| DRW Securities, LLC |
13F
Company
|
0.2%
|
$14,495
23,763 shares
|
— | 31 Mar 2026 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
Forms 3/4/5 flow
Insider trading overview
Net insider flow leans to selling over the last 12 months. Net value: -$284.
Buys
$0
Insiders: 0
Sells
$284
Insiders: 1
Net
-$284
Shares: -157
Window
Last 12 months
4 rolling buckets
Buy value
Sell value
Shares: 0
Shares: 157
| Window (months) | Buy shares | Sell shares | Buy value | Sell value | Net value |
|---|---|---|---|---|---|
| 0-3 | 0 | 0 | $0 | $0 | $0 |
| 3-6 | 0 | 0 | $0 | $0 | $0 |
| 6-9 | 0 | 157 | $0 | $284 | -$284 |
| 9-12 | 0 | 0 | $0 | $0 | $0 |
Reporting owners
Insider holders from Forms 3/4/5
Showing 1-16 of 16 reporting-owner rows connected to SYNLOGIC, INC.. Open a relationship link for the CIK-to-CIK filing trail.
Rows
16
Largest Forms 3/4/5 holder
Funicular Funds, LP
Net 12M change
-$284
Latest report
29 Oct 2025
Recent insider transactions for SYNLOGIC, INC.
Showing up to 300 recent insider transactions from the last 12 months.
| Insider | Symbol | Class | Transaction | % | SEC-reported value | SEC-reported price | Shares | Shares owned | Date | Ownership |
|---|---|---|---|---|---|---|---|---|---|---|
| Mary Beth Dooley | SYBX | Common Stock | Sale | -1.22% | $284 | $1.81 | -157 | 12,744 | 29 Oct 2025 | Direct |
* marks a reported price that did not pass the local price check.