---
schema_version: "secwatch.filing_event.v1"
accession: "0001537435-26-000072"
form_type: "8-K"
ticker: "TGEN"
cik: "0001537435"
company_name: "TECOGEN INC."
filed_at: "2026-08-31T21:23:20+00:00"
generated_at: "2026-08-31T21:24:33.146073+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.4
calibrated_materiality_score: 0.4
confidence: "high"
source: SEC EDGAR
---

# Tecogen registers 4.5M shares for resale; Hatsopoulos trusts agree to 182-day lock-up

## Summary
- Filed Form S-3 to register 4,507,603 shares of common stock for resale by selling stockholders.
- Shares were acquired in private placements exempt from SEC registration; no offer until S-3 effective.
- Hatsopoulos 2012 Family Trust and GST non-exempt QTIP Marital Trust (3,475,714 shares) signed lock-up agreements.
- Lock-up restricts sales for 182 calendar days after SEC declares S-3 effective; limited exceptions apply.
- Exceptions include transfers to trust beneficiaries, divorce court orders, and existing 10b5-1 plans.

## SEC filing metadata
- accession: 0001537435-26-000072
- form_type: 8-K
- ticker: TGEN
- cik: 0001537435
- company_name: TECOGEN INC.
- filed_at: 2026-08-31T21:23:20+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.4
- calibrated_materiality_score: 0.4
- confidence: high
- sec_items: 8.01, 9.1
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1537435/000153743526000072/0001537435-26-000072-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1537435/000153743526000072/tgen-20260831.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001537435-26-000072
- JSON: https://secwatch.observer/filing/0001537435-26-000072.json
- Plain text: https://secwatch.observer/filing/0001537435-26-000072.txt

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