---
schema_version: "secwatch.filing_event.v1"
accession: "0001515156-25-000085"
form_type: "8-K"
ticker: "ARQ"
cik: "0001515156"
company_name: "Arq, Inc."
filed_at: "2025-06-09T23:59:59+00:00"
generated_at: "2026-05-19T17:04:49.693438+00:00"
event_type: "other"
sentiment: "neutral"
materiality_score: 0.2
calibrated_materiality_score: 0.2
confidence: "high"
source: SEC EDGAR
---

# Arq changes auditor to Baker Tilly after Moss Adams merger

## Summary
- Moss Adams merged with Baker Tilly effective June 3, 2025; Moss Adams resigned as auditor.
- Audit committee approved Baker Tilly as successor independent registered public accounting firm.
- No disagreements or reportable events occurred during Moss Adams' tenure or interim period.
- Moss Adams' letter to the SEC agreeing with disclosures is filed as Exhibit 16.1.

## SEC filing metadata
- accession: 0001515156-25-000085
- form_type: 8-K
- ticker: ARQ
- cik: 0001515156
- company_name: Arq, Inc.
- filed_at: 2025-06-09T23:59:59+00:00
- event_type: other
- sentiment: neutral
- materiality_score: 0.2
- calibrated_materiality_score: 0.2
- confidence: high
- sec_items: 4.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1515156/000151515625000085/0001515156-25-000085-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1515156/000151515625000085/ades-20250603.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001515156-25-000085
- JSON: https://secwatch.observer/filing/0001515156-25-000085.json
- Plain text: https://secwatch.observer/filing/0001515156-25-000085.txt

## Key facts
- Auditor Changes
  Moss Adams, LLP resigned as auditor of Arq, Inc..
  - Action: resignation
  - Auditor: Moss Adams, LLP
  - Successor: Baker Tilly US, LLP
  source text: (the “Company”), was notified that Moss Adams, LLP (“Moss Adams”), the Company's independent registered public accounting firm, merged with Baker Tilly US, LLP, effective June 3, 2025.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1515156/000151515625000085/0001515156-25-000085-index.htm
- Auditor Changes
  Arq, Inc. engaged Baker Tilly US, LLP as its auditor.
  - Action: engagement
  - Auditor: Baker Tilly US, LLP
  source text: the Audit Committee of the Company's Board of Directors approved the appointment of Baker Tilly to succeed Moss Adams as the Company's independent registered public accounting firm
  evidence_url: https://www.sec.gov/Archives/edgar/data/1515156/000151515625000085/0001515156-25-000085-index.htm

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