Comparable stake leader
FMR LLC
SEC ownership of Seres Therapeutics, Inc.
Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0001609809.
Disclosed value leader
Nutritional Health LTP Fund General Partner LLC
Comparable rows
35/50
Latest evidence
15 Aug 2026
- Public ticker
- MCRB on Nasdaq
- Parsed ownership sources
-
13D/G, 13F, and 3/4/5
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
- Largest SEC-reported holder
-
FMR LLC
Ranking: Comparable ownership first, then disclosed value
- Comparable ownership rows
-
35 of 50
Meaning: Rows with safely comparable ownership %
- Latest 13D/G holder
-
FMR LLC
Source: Latest parsed Schedule 13D/G stake
- Latest parsed ownership date
-
15 Aug 2026
Freshness: Most recent filing date in this holder set
- Issuer CIK
- 0001609809
- Issuer location
- Cambridge, MA
Ownership snapshot
CIK-linked ownership evidence from parsed SEC filings.
3 signals
Issuer
Names, identifiers, and filing context for this profile.
2 identity fields
Ownership snapshot
Top shareholders of Seres Therapeutics, 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
FMR LLC
Disclosed value leader
Nutritional Health LTP Fu...
Comparable rows
35/50
Latest evidence
15 Aug 2026
13D/G
13F
3/4/5
Lead comparable stake: 3.1%
15 rows are not safely comparable across share classes.
13D/G row: FMR LLC
Showing 1-8 of 50 holder rows.
Quick read
FMR LLC leads the comparable SEC ownership view at 3.1%.
35 of 50 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 FMR LLC's linked filing trail.
Comparable ownership
Top 5
FMR LLC
3.1%
Flagship Pioneering, LLC
13%
VANGUARD CAPITAL MANAGEMENT LLC
3.3%
MARSHALL WACE, LLP
2%
Vontobel Holding Ltd.
1.4%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-8 of 50 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| FMR LLC |
13D/G
13F
Company
|
3.1%
|
$3,377,609
268,704 shares
|
-$2,827,043 | 30 Jun 2025 |
| Flagship Pioneering, LLC |
13F
Company
|
13%
|
$9,119,658
1,155,850 shares
|
— | 30 Jun 2026 |
| VANGUARD CAPITAL MANAGEMENT LLC |
13F
Company
|
3.3%
|
$2,270,553
287,776 shares
|
— | 30 Jun 2026 |
| MARSHALL WACE, LLP |
13F
Company
|
2%
|
$1,359,016
172,245 shares
|
— | 30 Jun 2026 |
| Vontobel Holding Ltd. |
13F
Company
|
1.4%
|
$970,273
122,975 shares
|
— | 30 Jun 2026 |
| BlackRock, Inc. |
13F
Company
|
1.3%
|
$875,790
111,000 shares
|
— | 30 Jun 2026 |
| GEODE CAPITAL MANAGEMENT, LLC |
13F
Company
|
0.92%
|
$631,301
79,974 shares
|
— | 30 Jun 2026 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP |
13F
Company
|
0.67%
|
$460,208
58,328 shares
|
— | 30 Jun 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: -$54,884.
Buys
$0
Insiders: 0
Sells
$54,884
Insiders: 5
Net
-$54,884
Shares: -4,057
Window
Last 12 months
4 rolling buckets
Buy value
Sell value
Shares: 0
Shares: 4,057
| Window (months) | Buy shares | Sell shares | Buy value | Sell value | Net value |
|---|---|---|---|---|---|
| 0-3 | 0 | 490 | $0 | $2,230 | -$2,230 |
| 3-6 | 0 | 474 | $0 | $3,569 | -$3,569 |
| 6-9 | 0 | 501 | $0 | $4,243 | -$4,243 |
| 9-12 | 0 | 2,592 | $0 | $44,842 | -$44,842 |
Reporting owners
Insider holders from Forms 3/4/5
Showing 1-20 of 24 reporting-owner rows connected to Seres Therapeutics, Inc.. Open a relationship link for the CIK-to-CIK filing trail.
Rows
24
Largest Forms 3/4/5 holder
Nutritional Health LTP Fund General Partner LLC
Net 12M change
-$54,883
Latest report
15 Aug 2026
Recent insider transactions for Seres Therapeutics, 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| Kelly M. Brady | MCRB | Common Stock | Sale | -0.73% | $291 | $4.55 | -64 | 8,679 | 17 Aug 2026 | Direct |
| Eric D. Shaff | MCRB | Common Stock | Sale | -2.06% | $1,197 | $4.55 | -263 | 12,499 | 17 Aug 2026 | Direct |
| Matthew R. Henn | MCRB | Common Stock | Sale | -1% | $369 | $4.55 | -81 | 7,995 | 17 Aug 2026 | Direct |
| Thomas J. DesRosier | MCRB | Common Stock | Sale | -1% | $373 | $4.55 | -82 | 8,117 | 17 Aug 2026 | Direct |
| Kelly M. Brady | MCRB | Common Stock | Options Exercise | 2.11% | 181 | 8,743 | 15 Aug 2026 | Direct | ||
| Kelly M. Brady | MCRB | Restricted Stock Units | Options Exercise | -50.3% | -181 | 179 | 15 Aug 2026 | Direct | ||
| Eric D. Shaff | MCRB | Common Stock | Options Exercise | 6% | 722 | 12,762 | 15 Aug 2026 | Direct | ||
| Eric D. Shaff | MCRB | Restricted Stock Units | Options Exercise | -48% | -722 | 783 | 15 Aug 2026 | Direct | ||
| Matthew R. Henn | MCRB | Common Stock | Options Exercise | 3.04% | 238 | 8,076 | 15 Aug 2026 | Direct | ||
| Matthew R. Henn | MCRB | Restricted Stock Units | Options Exercise | -45.8% | -238 | 282 | 15 Aug 2026 | Direct | ||
| Thomas J. DesRosier | MCRB | Common Stock | Options Exercise | 3.08% | 245 | 8,199 | 15 Aug 2026 | Direct | ||
| Thomas J. DesRosier | MCRB | Restricted Stock Units | Options Exercise | -48% | -245 | 265 | 15 Aug 2026 | Direct | ||
| Kurt Graves | MCRB | Stock Option (right to buy) | Award | 6,500 | 6,500 | 08 Jul 2026 | Direct | |||
| Richard N. Kender | MCRB | Stock Option (right to buy) | Award | 50,000 | 50,000 | 08 Jul 2026 | Direct | |||
| Matthew R. Henn | MCRB | Stock Option (right to buy) | Award | 25,000 | 25,000 | 08 Jul 2026 | Direct | |||
| Marella Thorell | MCRB | Stock Option (right to buy) | Award | 7,500 | 7,500 | 08 Jul 2026 | Direct | |||
| Claire Fraser | MCRB | Stock Option (right to buy) | Award | 6,500 | 6,500 | 08 Jul 2026 | Direct | |||
| Willard H. Dere | MCRB | Stock Option (right to buy) | Award | 6,500 | 6,500 | 08 Jul 2026 | Direct | |||
| Dennis A. Ausiello | MCRB | Stock Option (right to buy) | Award | 6,500 | 6,500 | 08 Jul 2026 | Direct | |||
| Eric D. Shaff | MCRB | Stock Option (right to buy) | Award | 6,500 | 6,500 | 08 Jul 2026 | Direct | |||
| Robert L. Rosiello | MCRB | Stock Option (right to buy) | Award | 6,500 | 6,500 | 08 Jul 2026 | Direct | |||
| Stephen Berenson | MCRB | Stock Option (right to buy) | Award | 6,500 | 6,500 | 08 Jul 2026 | Direct | |||
| Thomas J. DesRosier | MCRB | Stock Option (right to buy) | Award | 7,500 | 7,500 | 08 Jul 2026 | Direct | |||
| Kelly M. Brady | MCRB | Stock Option (right to buy) | Award | 18,750 | 18,750 | 08 Jul 2026 | Direct | |||
| Stephen Berenson | MCRB | Stock Option (right to buy) | Award | 7,508 | 7,508 | 01 Jul 2026 | Direct | |||
| Robert L. Rosiello | MCRB | Stock Option (right to buy) | Award | 7,508 | 7,508 | 01 Jul 2026 | Direct | |||
| Dennis A. Ausiello | MCRB | Stock Option (right to buy) | Award | 7,508 | 7,508 | 01 Jul 2026 | Direct | |||
| Eric D. Shaff | MCRB | Common Stock | Sale | -2.11% | $1,950 | $7.53 | -259 | 12,040 | 18 May 2026 | Direct |
| Thomas J. DesRosier | MCRB | Common Stock | Sale | -0.98% | $595 | $7.53 | -79 | 7,954 | 18 May 2026 | Direct |
| Kelly M. Brady | MCRB | Common Stock | Sale | -0.68% | $444 | $7.53 | -59 | 8,562 | 18 May 2026 | Direct |
| Matthew R. Henn | MCRB | Common Stock | Sale | -0.97% | $580 | $7.53 | -77 | 7,838 | 18 May 2026 | Direct |
| Eric D. Shaff | MCRB | Common Stock | Options Exercise | 6.24% | 722 | 12,299 | 15 May 2026 | Direct | ||
| Eric D. Shaff | MCRB | Restricted Stock Units | Options Exercise | -38.1% | -722 | 1,173 | 15 May 2026 | Direct | ||
| Thomas J. DesRosier | MCRB | Common Stock | Options Exercise | 3.13% | 244 | 8,033 | 15 May 2026 | Direct | ||
| Thomas J. DesRosier | MCRB | Restricted Stock Units | Options Exercise | -38% | -244 | 398 | 15 May 2026 | Direct | ||
| Kelly M. Brady | MCRB | Common Stock | Options Exercise | 2.13% | 180 | 8,621 | 15 May 2026 | Direct | ||
| Kelly M. Brady | MCRB | Restricted Stock Units | Options Exercise | -40.1% | -180 | 269 | 15 May 2026 | Direct | ||
| Matthew R. Henn | MCRB | Common Stock | Options Exercise | 3.1% | 238 | 7,915 | 15 May 2026 | Direct | ||
| Matthew R. Henn | MCRB | Restricted Stock Units | Options Exercise | -36.1% | -238 | 422 | 15 May 2026 | Direct | ||
| Kelly M. Brady | MCRB | Stock Option (right to buy) | Award | 56,250 | 56,250 | 04 Mar 2026 | Direct | |||
| Richard N. Kender | MCRB | Stock Option (right to buy) | Award | 150,000 | 150,000 | 04 Mar 2026 | Direct | |||
| Matthew R. Henn | MCRB | Stock Option (right to buy) | Award | 75,000 | 75,000 | 04 Mar 2026 | Direct | |||
| Marella Thorell | MCRB | Stock Option (right to buy) | Award | 22,500 | 22,500 | 04 Mar 2026 | Direct | |||
| Thomas J. DesRosier | MCRB | Stock Option (right to buy) | Award | 22,500 | 22,500 | 04 Mar 2026 | Direct | |||
| Eric D. Shaff | MCRB | Common Stock | Sale | -2.19% | $2,194 | $8.47 | -259 | 11,577 | 15 Feb 2026 | Direct |
| Eric D. Shaff | MCRB | Common Stock | Options Exercise | 6.51% | 723 | 11,836 | 15 Feb 2026 | Direct | ||
| Eric D. Shaff | MCRB | Restricted Stock Units | Options Exercise | -31.6% | -724 | 1,564 | 15 Feb 2026 | Direct | ||
| Teresa L. Young | MCRB | Common Stock | Sale | -0.87% | $635 | $8.47 | -75 | 8,557 | 15 Feb 2026 | Direct |
| Teresa L. Young | MCRB | Common Stock | Options Exercise | 2.75% | 231 | 8,632 | 15 Feb 2026 | Direct | ||
| Teresa L. Young | MCRB | Restricted Stock Units | Options Exercise | -30.3% | -231 | 531 | 15 Feb 2026 | Direct |
* marks a reported price that did not pass the local price check.