---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-21-366358"
form_type: "8-K"
ticker: "PRTA"
cik: "0001559053"
company_name: "PROTHENA CORP PUBLIC LTD CO"
filed_at: "2021-12-23T23:59:59+00:00"
generated_at: "2026-06-27T22:35:15.190240+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Prothena enters $250M at-the-market equity distribution agreement

## Summary
- Agreement with Piper Sandler, Stifel, Cantor Fitzgerald, RBC Capital Markets, and JMP Securities.
- Company may sell up to $250M of ordinary shares from time to time via ATM offerings.
- Agents receive up to 3% commission on gross proceeds; company may set minimum sale price.
- Offering terminates upon sale of all shares or earlier termination by either party.
- Company is not obligated to sell any shares under the agreement.

## SEC filing metadata
- accession: 0001193125-21-366358
- form_type: 8-K
- ticker: PRTA
- cik: 0001559053
- company_name: PROTHENA CORP PUBLIC LTD CO
- filed_at: 2021-12-23T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1559053/000119312521366358/0001193125-21-366358-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1559053/000119312521366358/d203387d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-21-366358
- JSON: https://secwatch.observer/filing/0001193125-21-366358.json
- Plain text: https://secwatch.observer/filing/0001193125-21-366358.txt

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