---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-22-307391"
form_type: "8-K"
ticker: "PRTA"
cik: "0001559053"
company_name: "PROTHENA CORP PUBLIC LTD CO"
filed_at: "2022-12-16T23:59:59+00:00"
generated_at: "2026-06-21T03:19:47.505746+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.7
calibrated_materiality_score: 0.7
confidence: "high"
source: SEC EDGAR
---

# Prothena launches $172.4M public offering of 3.25M ordinary shares at $53.11/share

## Summary
- Underwriters agreed to buy 3,250,000 ordinary shares at $53.11 per share; 30-day option for up to 487,500 additional shares.
- Net proceeds expected to be approximately $172.4 million after discounts and expenses, assuming no underwriter option exercise.
- Offering expected to close on December 19, 2022; lock-up agreements for directors, officers, and certain shareholders for 90 days.
- Proceeds intended for general corporate purposes; underwriting agreement includes customary indemnification provisions.

## SEC filing metadata
- accession: 0001193125-22-307391
- form_type: 8-K
- ticker: PRTA
- cik: 0001559053
- company_name: PROTHENA CORP PUBLIC LTD CO
- filed_at: 2022-12-16T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.7
- calibrated_materiality_score: 0.7
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1559053/000119312522307391/0001193125-22-307391-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1559053/000119312522307391/d378186d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-22-307391
- JSON: https://secwatch.observer/filing/0001193125-22-307391.json
- Plain text: https://secwatch.observer/filing/0001193125-22-307391.txt

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