---
schema_version: "secwatch.filing_event.v1"
accession: "0001877939-25-000042"
form_type: "8-K"
ticker: "CTM"
cik: "0001877939"
company_name: "Castellum, Inc."
filed_at: "2025-04-15T23:59:59+00:00"
generated_at: "2026-05-23T14:59:11.133302+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.35
calibrated_materiality_score: 0.35
confidence: "high"
source: SEC EDGAR
---

# Castellum subsidiary GTMR adds Professional Services SIN 541611 to GSA MAS contract

## Summary
- GTMR added SIN 541611 (management/financial consulting, acquisition support, program management) to its GSA MAS contract.
- Previously held SINs for engineering, testing, system design, and R&D services.
- New SIN allows GTMR to bid on competitive RFQs/RFPs in professional services.
- COO Drew Merriman highlights organic growth and ability to leverage joint ventures with this expansion.

## SEC filing metadata
- accession: 0001877939-25-000042
- form_type: 8-K
- ticker: CTM
- cik: 0001877939
- company_name: Castellum, Inc.
- filed_at: 2025-04-15T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.35
- calibrated_materiality_score: 0.35
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1877939/000187793925000042/0001877939-25-000042-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1877939/000187793925000042/ctm-20250415.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001877939-25-000042
- JSON: https://secwatch.observer/filing/0001877939-25-000042.json
- Plain text: https://secwatch.observer/filing/0001877939-25-000042.txt

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