Across its top 20 institutional holders, MCRB's holder base skews toward low-concentration, low-turnover investors on average (avg. concentration score 11/100, avg. turnover score 31/100).

Quarterly Activity

Recent Activity

+$3.5M

Total Buy Value

$13.4M

Total Sell Value

New buy2

Trim10

Add10

Sold out9

Net Buyers

Net Sellers

Smart Money Convergence

MCRB does not currently have enough recent insider (Form 4) trading activity to compute a convergence signal against its 13F institutional flows.

13F data as of 2026-03-31 quarterly filings. Note: many large institutions file close to the 45-day post-quarter deadline, so early-quarter flow figures can shift substantially as more filings arrive.

Insider Trading (Form 4)

Form 144 Pre-Sale Notices

No Form 144 planned sale filings in the last 90 days

Beneficial Ownership (13D/13G)

No Schedule 13D/13G filings for this ticker

Material Events (8-K)

Filings (14d)

Data as of 2026-07-08

2026-07-08

No AI summary for this filing type

View Full Filing (SEC EDGAR)

2026-07-08

Seres Therapeutics (ticker: MCRB) held its annual shareholder meeting on July 8, 2026, after an earlier adjournment due to lack of a quorum. Shareholders voted to amend the company's 2025 Incentive Award Plan, increasing the share pool by 900,000 shares.

View Full Filing (SEC EDGAR)

View all Form 8-K filings

CUSIP

81750R201

FAQ

Who are the top institutional investors holding SERES THERAPEUTICS INC (MCRB)?

Major stakeholders currently include Flagship Pioneering, LLC ($10.3M), Vanguard Capital Management LLC ($2.6M), Susquehanna International Group, LLP ($2.0M). Based on the latest 13F filings, there are a total of 34 tracked investment funds and institutions maintaining positions in MCRB.

What is the overall institutional sentiment toward MCRB recently?

Institutional sentiment appears Bearish (Net Selling). During the most recent reporting quarter, the stock experienced a net outflow of $18.8M, driven by 12 managers accumulating shares while 19 reduced their exposure.

Which institutions have been selling or reducing their MCRB positions?

In the latest period, 10 funds trimmed their holdings, and 9 managers completely exited their positions. The aggregate reported sell value was $13.4M.

Are there any notable investors adding MCRB to their portfolios?

Yes, buying activity remains notable. 2 institutions opened new positions in {ticker}, and 10 existing holders added to their shares. The total reported buy value for the quarter amounted to $3.5M.