MCRB · Insider trading · 13F holders · Congress trades
Seres Therapeutics, Inc. (MCRB)
Who is buying and selling MCRB: company insiders on SEC Form 4, hedge funds and superinvestors on Form 13F, and members of Congress under the STOCK Act. Every figure links to the filing or page it comes from.
- 13F filers holding
- 2
- Insider buys, 90 days
- $0
- Insider sales, 90 days
- $2K
- Congress trades, 12 months
- 0
MCRB at a glance
- Between Aug 1, 2026 and Oct 29, 2026, 4 MCRB insiders filed 4 sales worth $2K on SEC Form 4, and no open-market purchases; 4 of the sales were pre-planned under Rule 10b5-1.
- 2 13F filers hold MCRB among their 50 largest positions, worth $9.4M combined. The biggest bets by portfolio weight are Lion Point Capital, LP (1.2%).
- No member of Congress has disclosed a trade in MCRB.
- MCRB last closed at $1.95 on Oct 29, 2026.
MCRB insider trading
Between Aug 1, 2026 and Oct 29, 2026, 4 MCRB insiders filed 4 sales worth $2K on SEC Form 4, and no open-market purchases; 4 of the sales were pre-planned under Rule 10b5-1.
| Filed | Insider | Role | Trade | Shares | Price | Value | Form 4 |
|---|---|---|---|---|---|---|---|
| Aug 18, 2026 | Shaff Eric D. | Director | Sale10b5-1 | 263 | $4.55 | $1K | SEC |
| Aug 18, 2026 | DesRosier Thomas | See Remarks | Sale10b5-1 | 82 | $4.55 | $373.10 | SEC |
| Aug 18, 2026 | Henn Matthew R | See Remarks | Sale10b5-1 | 81 | $4.55 | $368.55 | SEC |
| Aug 18, 2026 | Brady Kelly | See Remarks | Sale10b5-1 | 64 | $4.55 | $291.20 | SEC |
Who owns MCRB? Hedge funds and superinvestors
2 13F filers hold MCRB among their 50 largest positions, worth $9.4M combined. The biggest bets by portfolio weight are Lion Point Capital, LP (1.2%).
| Manager | % of portfolio | Value | Shares | Last quarter | 13F |
|---|---|---|---|---|---|
| Flagship Pioneering, LLCHedge fund | 0.6% | $9.1M | 1,155,850 | +0.0% shares | Q2 2026 |
| Lion Point Capital, LPHedge fund | 1.2% | $249K | 31,570 | +0.0% shares | Q2 2026 |
Each manager counts with its latest 13F (Q2 2026: 2). Screen MCRB in the grand portfolio →
MCRB stock trades by members of Congress
No member of Congress has disclosed a trade in MCRB.
MCRB questions and answers
Are insiders buying MCRB stock?
Between Aug 1, 2026 and Oct 29, 2026, 4 MCRB insiders filed 4 sales worth $2K on SEC Form 4, and no open-market purchases; 4 of the sales were pre-planned under Rule 10b5-1.
Which hedge funds own MCRB?
2 13F filers hold MCRB among their 50 largest positions, worth $9.4M combined. The biggest bets by portfolio weight are Lion Point Capital, LP (1.2%).
Has Congress traded MCRB?
No member of Congress has disclosed a trade in MCRB.
Who is the largest holder of MCRB?
Among 13F filers, Flagship Pioneering, LLC reports the largest MCRB position, $9.1M (1,155,850 shares) in its Q2 2026 13F. The biggest bet by portfolio weight is Lion Point Capital, LP's: 1.2% of its portfolio.
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