---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-26-371263"
form_type: "8-K"
ticker: "ETCG"
cik: "0001705181"
company_name: "Grayscale Ethereum Classic Trust (ETC)"
filed_at: "2026-08-27T20:06:02+00:00"
generated_at: "2026-08-27T20:08:07.769490+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.3
calibrated_materiality_score: 0.3
confidence: "high"
source: SEC EDGAR
---

# Grayscale Ethereum Classic Trust to adopt new CoinDesk benchmark index for NAV from Sept 1, 2026

## Summary
- Effective Sept 1, 2026, NAV uses CoinDesk Ethereum Classic Benchmark Extended Rate, replacing Price Index.
- New index methodology includes volume weighting, outlier detection, inactivity adjustments, and manipulation resistance.
- Index provider can adjust methodology without consent; sponsor may use cascading fallback indices if unavailable.
- Change affects only NAV calculation; underlying ETC holdings and operational structure remain unchanged.

## SEC filing metadata
- accession: 0001193125-26-371263
- form_type: 8-K
- ticker: ETCG
- cik: 0001705181
- company_name: Grayscale Ethereum Classic Trust (ETC)
- filed_at: 2026-08-27T20:06:02+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.3
- calibrated_materiality_score: 0.3
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1705181/000119312526371263/0001193125-26-371263-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1705181/000119312526371263/etcg-20260827.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-26-371263
- JSON: https://secwatch.observer/filing/0001193125-26-371263.json
- Plain text: https://secwatch.observer/filing/0001193125-26-371263.txt

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