Seres Therapeutics
MCRB on Nasdaq. Market value $28m.
Should I look at this?
Look carefully before going further
Why it could be worth it
Nothing stands out yet.
What to watch out for
Read the warning sign in its own filings
This is not advice.
Who owns it
None of the long-term investors we follow own it. 36 funds in all.
Largest holders overall
- Flagship Pioneering$9m
- Vanguard Capital Management$2mCut
- Marshall Wace, LLP$1mAdded
- Vontobel Holding$970,273Cut
- BlackRock$875,790Added
- Geode Capital Management$631,301Added
- Susquehanna International Group, LLP$460,208Cut
- Vanguard Fiduciary Trust$384,125Added
- State Street$267,479
- Lion Point Capital, LP$249,087
From 13F filings for the quarter ended 30 June 2026.
Big holders and activists
1 investor owns more than 5%.
From Schedule 13D and 13G filings: anyone owning more than 5% must file one.
What insiders did
No insider bought shares on the open market in the last 12 months. 5 sold $54,884, $54,440 of it under preset trading plans.
- Brady KellySee RemarksSoldunder a preset trading plan
- Date
- 17 August 2026
- Shares
- 64
- Price
- $4.55
- Value
- $291
- Shaff Eric D.DirectorSoldunder a preset trading plan
- Date
- 17 August 2026
- Shares
- 263
- Price
- $4.55
- Value
- $1,197
- Henn Matthew RSee RemarksSoldunder a preset trading plan
- Date
- 17 August 2026
- Shares
- 81
- Price
- $4.55
- Value
- $369
- DesRosier ThomasSee RemarksSoldunder a preset trading plan
- Date
- 17 August 2026
- Shares
- 82
- Price
- $4.55
- Value
- $373
- Shaff Eric D.DirectorSoldunder a preset trading plan
- Date
- 18 May 2026
- Shares
- 259
- Price
- $7.53
- Value
- $1,950
- Brady KellySee RemarksSold
- Date
- 18 May 2026
- Shares
- 59
- Price
- $7.53
- Value
- $444
- DesRosier ThomasSee RemarksSoldunder a preset trading plan
- Date
- 18 May 2026
- Shares
- 79
- Price
- $7.53
- Value
- $595
- Henn Matthew RSee RemarksSoldunder a preset trading plan
- Date
- 18 May 2026
- Shares
- 77
- Price
- $7.53
- Value
- $580
- Young Teresa L.See RemarksSoldunder a preset trading plan
- Date
- 15 February 2026
- Shares
- 75
- Price
- $8.47
- Value
- $635
- Shaff Eric D.DirectorSoldunder a preset trading plan
- Date
- 15 February 2026
- Shares
- 259
- Price
- $8.47
- Value
- $2,194
| Date | Who | Did | Shares | Price | Value |
|---|---|---|---|---|---|
| 17 August 2026 | Brady Kelly See Remarks | Sold under a preset trading plan | 64 | $4.55 | $291 |
| 17 August 2026 | Shaff Eric D. Director | Sold under a preset trading plan | 263 | $4.55 | $1,197 |
| 17 August 2026 | Henn Matthew R See Remarks | Sold under a preset trading plan | 81 | $4.55 | $369 |
| 17 August 2026 | DesRosier Thomas See Remarks | Sold under a preset trading plan | 82 | $4.55 | $373 |
| 18 May 2026 | Shaff Eric D. Director | Sold under a preset trading plan | 259 | $7.53 | $1,950 |
| 18 May 2026 | Brady Kelly See Remarks | Sold | 59 | $7.53 | $444 |
| 18 May 2026 | DesRosier Thomas See Remarks | Sold under a preset trading plan | 79 | $7.53 | $595 |
| 18 May 2026 | Henn Matthew R See Remarks | Sold under a preset trading plan | 77 | $7.53 | $580 |
| 15 February 2026 | Young Teresa L. See Remarks | Sold under a preset trading plan | 75 | $8.47 | $635 |
| 15 February 2026 | Shaff Eric D. Director | Sold under a preset trading plan | 259 | $8.47 | $2,194 |
From Form 4 filings: insiders must report trades in their own company's shares within two days.
Warning signs in its filings
Problems the company itself reported to the SEC, in its own words.
1 serious warning sign in Seres Therapeutics’ filings.
We look for five warning signs: doubt it can keep going, weak checks on its own accounts, a notice that its past accounts can't be relied on, a change of auditor, and one customer bringing in a big share of sales. We don't check lawsuits, investigations or debt yet.
We checked the auditor's report, internal controls, restatement notices, auditor changes and big customers in the 10-K filed 12 Mar 2026, plus the 10-Q filed 5 Aug 2026 and 8 later 8-Ks.
Doubt it can keep going
SeriousThe company or its auditor warned it may not have enough money to last the next year.
“These conditions raise substantial doubt about the Company’s ability to continue as a going concern.”
Show the full paragraph
Primarily as a result of the costs associated with the discovery and development of novel live biotherapeutics, the Company incurred a net loss from operations of $ 42,180 for the six months ended June 30, 2026 . The Company expects that its operating losses and negative cash flows will continue for the foreseeable future. Based on the Company’s currently available cash resources, the $ 12,500 Milestone Termination Payment (as defined below in Note 3, Discontinued Operations and TSA ) received from SPN (as defined below) in July 2026, and the expected receipt of the additional $ 12,500 Milestone Termination Payment due from SPN in October 2026 , current and forecasted level of operations, and forecasted cash flows for the 12-month period subsequent to the date of issuance of these condensed consolidated financial statements, the Company will require additional funding to support its ongoing operations and meet its obligations as they come due. These conditions raise substantial doubt about the Company’s ability to continue as a going concern.
From the 10-Q filed 5 August 2026, Part I, Item 1. Financial Statements. Read it in the filing
A 10-K is the yearly report every US company files with the SEC. An 8-K is a short notice of a big event.
The deep dive
Everything above is arithmetic on public filings. The deep dive reads the last ten years of annual reports, the proxy statements, and the earnings calls, then argues the case the way Buffett, Klarman, and Hohn would, and checks every claim against the source.
- What the business is worth, as a range, and the margin of safety at today’s price
- Prices to start buying, buy, and buy hard
- The three things that would make this a mistake
- Every number footnoted to the filing it came from
Your first deep dive is free.
Not advice. Numbers on this page come from SEC filings and are updated each night; prices are updated again after the US market closes. The five-year figures are rounded.