Seres Therapeutics, Inc. (MCRB) Insider Trading
Over the last 3 months, MCRB insiders made 0 open-market buys and 4 sales, a net sale of -$4K (SEC Form 4). Over the last 6 months, 27 institutions increased and 15 reduced their position (13F).
Insider Activity
Sentiment
0/100
Buys (3m)
0
Sells (3m)
4
Net (3m)
-$3.6K
Insider trades by month Buys Sells
Feb
May
Aug
Nov
Feb
May
Context3-month price -21.5%Institutions accumulating (13F)
| Date | Insider | Type | Shares | Price |
|---|---|---|---|---|
| May 19, 2026 | DesRosier Thomasofficer: See Remarks | Option | 133 | — |
| May 19, 2026 | DesRosier Thomasofficer: See Remarks | Option | 244 | — |
| May 19, 2026 | Brady Kellyofficer: See Remarks | Option | 91 | — |
| May 19, 2026 | Shaff Eric D.director | Option | 722 | — |
| May 19, 2026 | DesRosier Thomasofficer: See Remarks | Sell | 79 | $7.53 |
| May 19, 2026 | Shaff Eric D.director | Option | 391 | — |
| May 19, 2026 | Brady Kellyofficer: See Remarks | Option | 89 | — |
| May 19, 2026 | Henn Matthew Rofficer: See Remarks | Sell | 77 | $7.53 |
| May 19, 2026 | Henn Matthew Rofficer: See Remarks | Option | 97 | — |
| May 19, 2026 | Henn Matthew Rofficer: See Remarks | Option | 141 | — |
| May 19, 2026 | Brady Kellyofficer: See Remarks | Sell | 59 | $7.53 |
| May 19, 2026 | Brady Kellyofficer: See Remarks | Option | 180 | — |
| May 19, 2026 | Shaff Eric D.director | Option | 331 | — |
| May 19, 2026 | Henn Matthew Rofficer: See Remarks | Option | 238 | — |
| May 19, 2026 | Shaff Eric D.director | Sell | 259 | $7.53 |
| May 19, 2026 | DesRosier Thomasofficer: See Remarks | Option | 111 | — |
| Mar 11, 2026 | Brady Kellyofficer: See Remarks | Grant | 56,250 | $9.13 |
| Mar 6, 2026 | Kender Richard Ndirector, officer: See Remarks | Grant | 150,000 | $9.13 |
| Mar 6, 2026 | DesRosier Thomasofficer: See Remarks | Grant | 22,500 | $9.13 |
| Mar 6, 2026 | Thorell Marellaofficer: See Remarks | Grant | 22,500 | $9.13 |
| Mar 6, 2026 | Henn Matthew Rofficer: See Remarks | Grant | 75,000 | $9.13 |
| Feb 18, 2026 | DesRosier Thomasofficer: See Remarks | Option | 133 | — |
| Feb 18, 2026 | Henn Matthew Rofficer: See Remarks | Option | 239 | — |
| Feb 18, 2026 | Henn Matthew Rofficer: See Remarks | Sell | 89 | $8.47 |
| Feb 18, 2026 | DesRosier Thomasofficer: See Remarks | Sell | 78 | $8.47 |
| Feb 18, 2026 | Shaff Eric D.director | Option | 391 | — |
| Feb 18, 2026 | Shaff Eric D.director | Option | 723 | — |
| Feb 18, 2026 | Henn Matthew Rofficer: See Remarks | Option | 98 | — |
| Feb 18, 2026 | DesRosier Thomasofficer: See Remarks | Option | 244 | — |
| Feb 18, 2026 | Henn Matthew Rofficer: See Remarks | Option | 141 | — |
Source: MCRB SEC Form 4 filings, latest May 19, 2026. For informational purposes only — not investment advice.
Institutional activity (13F)
How institutions changed their MCRB positions over the last 6 months (SEC Form 13F).
Increased
27
New positions
14
Reduced
15
Sold out
17
Largest moves
| Institution | Action | Shares | Filed |
|---|---|---|---|
| FLAGSHIP PIONEERING INC. | Unchanged | 1.2M | May 15, 2026 |
| FLAGSHIP PIONEERING INC. | Unchanged | 1.2M | Feb 17, 2026 |
| VANGUARD GROUP INC | Increased | 324K | Jan 29, 2026 |
| VANGUARD CAPITAL MANAGEMENT LLC | New Position | 294K | May 15, 2026 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Increased | 180K | Feb 17, 2026 |
| MARSHALL WACE, LLP | Increased | 140K | May 15, 2026 |
| VONTOBEL HOLDING LTD. | Increased | 138K | May 8, 2026 |
| HUDSON BAY CAPITAL MANAGEMENT LP | New Position | 125K | Dec 15, 2025 |
| MARSHALL WACE, LLP | Reduced | 120K | Feb 13, 2026 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Reduced | 105K | May 15, 2026 |
| BLACKROCK, INC. | Increased | 104K | Feb 12, 2026 |
| VONTOBEL HOLDING LTD. | Increased | 103K | Feb 13, 2026 |
| BLACKROCK, INC. | Reduced | 102K | May 13, 2026 |
| GEODE CAPITAL MANAGEMENT, LLC | Increased | 86K | Feb 9, 2026 |
| CAPTION MANAGEMENT, LLC | Unchanged | 75K | Feb 17, 2026 |
Source: SEC Form 13F filings. For informational purposes only — not investment advice.