---
schema_version: "secwatch.filing_event.v1"
accession: "0001104659-26-029952"
form_type: "8-K"
ticker: "ENZN"
cik: "0000727510"
company_name: "Viskase Holdings, Inc."
filed_at: "2026-03-18T23:59:59+00:00"
generated_at: "2026-05-15T09:59:31.577837+00:00"
event_type: "other"
sentiment: "neutral"
materiality_score: 0.2
calibrated_materiality_score: 0.2
confidence: "high"
source: SEC EDGAR
---

# Enzon extends shareholder rights plan expiration to March 24, 2026 via Tenth Amendment

## Summary
- Tenth Amendment to Section 382 Rights Agreement extends Final Expiration Date from noon March 18 to noon March 24, 2026.
- Rights Agreement otherwise remains unmodified; this is the tenth successive short-term extension since June 2024.
- Company states extension is in best interests of Enzon and its stockholders.

## SEC filing metadata
- accession: 0001104659-26-029952
- form_type: 8-K
- ticker: ENZN
- cik: 0000727510
- company_name: Viskase Holdings, Inc.
- filed_at: 2026-03-18T23:59:59+00:00
- event_type: other
- sentiment: neutral
- materiality_score: 0.2
- calibrated_materiality_score: 0.2
- confidence: high
- sec_items: 1.01, 3.03, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/727510/000110465926029952/0001104659-26-029952-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/727510/000110465926029952/tm267491d4_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001104659-26-029952
- JSON: https://secwatch.observer/filing/0001104659-26-029952.json
- Plain text: https://secwatch.observer/filing/0001104659-26-029952.txt

## Key facts
- Material Agreements
  Viskase Holdings, Inc. amended Tenth Amendment to Section 382 Rights Agreement with Continental Stock Transfer & Trust Company (effective 2026-03-18).
  - Action: amendment
  - Counterparty: Continental Stock Transfer & Trust Company
  - Effective: 2026-03-18
  source text: On March 18, 2026, Enzon Pharmaceuticals, Inc. (the “ Company ”) entered into the Tenth Amendment to the Section 382 Rights Agreement (the “ Tenth Amendment ”)
  evidence_url: https://www.sec.gov/Archives/edgar/data/727510/000110465926029952/0001104659-26-029952-index.htm

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