---
schema_version: "secwatch.filing_event.v1"
accession: "0001641172-25-012481"
form_type: "8-K"
ticker: "GTBP"
cik: "0000109657"
company_name: "GT Biopharma, Inc."
filed_at: "2025-05-27T23:59:59+00:00"
generated_at: "2026-05-20T10:01:53.522678+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.5
calibrated_materiality_score: 0.5
confidence: "high"
source: SEC EDGAR
---

# GT Biopharma expands private placement to $5.95M, adds new investor Marzilli

## Summary
- Increased Series L preferred offering to 6,612 shares ($5.95M) from 6,056 shares ($5.45M) via First Amendment on May 21, 2025.
- Added Robert A. Marzilli as new purchaser; Majority Purchasers (Five Narrow Lane, Bristol Capital) consented.
- Filed Certificate of Increase raising authorized Series L shares from 28,056 to 30,630.
- Greenshoe right: Purchasers may buy up to $24.0M additional preferred stock on same terms.

## SEC filing metadata
- accession: 0001641172-25-012481
- form_type: 8-K
- ticker: GTBP
- cik: 0000109657
- company_name: GT Biopharma, Inc.
- filed_at: 2025-05-27T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.5
- calibrated_materiality_score: 0.5
- confidence: high
- sec_items: 1.01, 3.02, 3.03, 5.03, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/109657/000164117225012481/0001641172-25-012481-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/109657/000164117225012481/form8-k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001641172-25-012481
- JSON: https://secwatch.observer/filing/0001641172-25-012481.json
- Plain text: https://secwatch.observer/filing/0001641172-25-012481.txt

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