---
schema_version: "secwatch.filing_event.v1"
accession: "0001140361-25-014937"
form_type: "8-K"
ticker: "ABCP"
cik: "0000020639"
company_name: "AmBase Corp"
filed_at: "2025-04-22T23:59:59+00:00"
generated_at: "2026-05-23T09:40:33.691860+00:00"
event_type: "other_material"
sentiment: "negative"
materiality_score: 0.6
calibrated_materiality_score: 0.6
confidence: "high"
source: SEC EDGAR
---

# AmBase auditor Marcum resigns; CBIZ CPAs engaged as new auditor

## Summary
- Marcum LLP resigned as independent registered public accounting firm on April 22, 2025; no disagreements or reportable events.
- Prior audit reports for FY2024 and FY2023 included a going-concern explanatory paragraph.
- CBIZ CPAs P.C., which acquired Marcum's attest business, was engaged as new auditor for FY2025 effective same date.
- Neither the company nor anyone on its behalf consulted CBIZ on accounting matters prior to engagement.

## SEC filing metadata
- accession: 0001140361-25-014937
- form_type: 8-K
- ticker: ABCP
- cik: 0000020639
- company_name: AmBase Corp
- filed_at: 2025-04-22T23:59:59+00:00
- event_type: other_material
- sentiment: negative
- materiality_score: 0.6
- calibrated_materiality_score: 0.6
- confidence: high
- sec_items: 4.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/20639/000114036125014937/0001140361-25-014937-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/20639/000114036125014937/ef20047722_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001140361-25-014937
- JSON: https://secwatch.observer/filing/0001140361-25-014937.json
- Plain text: https://secwatch.observer/filing/0001140361-25-014937.txt

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