---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-26-205009"
form_type: "8-K"
ticker: "MCRB"
cik: "0001609809"
company_name: "Seres Therapeutics, Inc."
filed_at: "2026-05-05T23:59:59+00:00"
generated_at: "2026-05-14T23:23:29.446338+00:00"
event_type: "earnings"
sentiment: "negative"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Seres Q1 2026 net loss $19.9M; cash runway only through Q3 2026

## Summary
- Net loss $19.9M vs net income $32.7M in Q1 2025 (which included $50M Nestlé payment).
- Cash and equivalents $29.8M as of March 31, 2026; expects to fund ops only through Q3 2026.
- R&D expenses $13.2M (up from $11.8M), G&A $8.1M (down from $11.9M); no manufacturing services expenses.
- SER-155 IST for immune checkpoint inhibitor-related enterocolitis enrollment complete (15 pts); data expected in coming weeks.
- SER-155 Phase 2 ready for allo-HSCT but seeking funding; SER-603 preclinical for IBD with IND-enabling activities ongoing.

## SEC filing metadata
- accession: 0001193125-26-205009
- form_type: 8-K
- ticker: MCRB
- cik: 0001609809
- company_name: Seres Therapeutics, Inc.
- filed_at: 2026-05-05T23:59:59+00:00
- event_type: earnings
- sentiment: negative
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 2.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1609809/000119312526205009/0001193125-26-205009-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1609809/000119312526205009/d155025d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-26-205009
- JSON: https://secwatch.observer/filing/0001193125-26-205009.json
- Plain text: https://secwatch.observer/filing/0001193125-26-205009.txt

## Source-grounded claims
- claim_id: 0f5e1643d9adad60cdab551aec5f804654de02d0
  claim: Seres Therapeutics, Inc. reported the quarter ended March 31, 2026 results: net income Net loss was $19.9 million for the first quarter of 2026.
  evidence_excerpt: Seres Therapeutics, Inc. announced its financial results for the quarter ended March 31, 2026 and provided operational updates.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1609809/000119312526205009/0001193125-26-205009-index.htm

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.