---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-24-199141"
form_type: "8-K"
ticker: "AMSC"
cik: "0000880807"
company_name: "AMERICAN SUPERCONDUCTOR CORP /DE/"
filed_at: "2024-08-13T23:59:59+00:00"
generated_at: "2026-05-31T09:55:05.408095+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.4
calibrated_materiality_score: 0.4
confidence: "medium"
source: SEC EDGAR
---

# AMSC files prospectus supplement for secondary offering by selling stockholders

## Summary
- Filed prospectus supplement on August 12, 2024 for shares to be sold by certain selling stockholders.
- Registration Statement on Form S-3 (333-281496) became effective the same day.
- Latham & Watkins issued opinion on validity of shares, filed as Exhibit 5.1.
- Company is not selling shares; offering is secondary from existing stockholders.

## SEC filing metadata
- accession: 0001193125-24-199141
- form_type: 8-K
- ticker: AMSC
- cik: 0000880807
- company_name: AMERICAN SUPERCONDUCTOR CORP /DE/
- filed_at: 2024-08-13T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.4
- calibrated_materiality_score: 0.4
- confidence: medium
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/880807/000119312524199141/0001193125-24-199141-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/880807/000119312524199141/d855585d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-24-199141
- JSON: https://secwatch.observer/filing/0001193125-24-199141.json
- Plain text: https://secwatch.observer/filing/0001193125-24-199141.txt

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