Seres Therapeutics
MCRB
33 hedge funds and large institutions have $20.5M invested in Seres Therapeutics in 2026 Q1 according to their latest regulatory filings, with 5 funds opening new positions, 10 increasing their positions, 8 reducing their positions, and 7 closing their positions.
25% more repeat investments, than reductions
Existing positions increased: 10 | Existing positions reduced: 8
0% more funds holding in top 10
Funds holding in top 10: 1 → 1 (0)
2.93% less ownership
Funds ownership: 26.99% → 24.06% (-2.9%)
8% less funds holding
Funds holding: 36 → 33 (-3)
29% less first-time investments, than exits
New positions opened: 5 | Existing positions closed: 7
29% less call options, than puts
Call options by funds: $958K | Put options by funds: $1.35M
44% less capital invested
Capital invested by funds: $36.4M → $20.5M (-$15.9M)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
American Century Companies
Kansas City,
Missouri
|
+$539K |
| 2 |
Vontobel Holding
Zurich,
Switzerland
|
+$413K |
| 3 |
Marshall Wace
London,
United Kingdom
|
+$227K |
| 4 |
UBS Group
Zurich,
Switzerland
|
+$32.8K |
| 5 |
Simplex Trading
Chicago,
Illinois
|
+$21.5K |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Susquehanna International Group
Bala Cynwyd,
Pennsylvania
|
-$874K |
| 2 |
6CM
683 Capital Management
New York
|
-$778K |
| 3 |
SSA
Schonfeld Strategic Advisors
New York
|
-$433K |
| 4 |
Citadel Advisors
Miami,
Florida
|
-$368K |
| 5 |
OAC
OMERS Administration Corp
Toronto,
Ontario, Canada
|
-$214K |
MCRB Hedge Fund Activity: Q1 2026 in Review
33 of the 8,136 institutional investors tracked by Wall St. Rank reported a position in Seres Therapeutics (MCRB) for Q1 2026, worth a combined $20.5M — down 44% from $36.4M a quarter earlier.
Sellers outnumbered buyers: 7 funds closed out of MCRB and 5 opened new positions — a net loss of 2 holders — while 8 trimmed existing stakes and 10 added.
The largest buyer was American Century Companies, adding an estimated $539K. The largest seller was Susquehanna International Group, cutting an estimated $874K.
- 33 institutional investors held Seres Therapeutics (MCRB) as of Q1 2026, down from 36 in Q4 2025.
- Funds reported $20.5M of Seres Therapeutics stock for Q1 2026, down 44% quarter-over-quarter.
- 5 funds opened new Seres Therapeutics positions in Q1 2026 and 7 closed out, a net change of -2 holders.
- The largest Seres Therapeutics buyer in Q1 2026 was American Century Companies, an estimated $539K added.
- The largest Seres Therapeutics seller in Q1 2026 was Susquehanna International Group, an estimated $874K sold.
Based on aggregated 13F filings for Q1 2026.