PROTHENA CORP PUBLIC LTD CO (PRTA)
As-reported financials and SEC filings for PROTHENA CORP PUBLIC LTD CO. The latest annual period is FY2025. The latest reported quarter is Q2 FY2026. Financial statements come straight from the company’s EDGAR filings; valuation figures such as P/E and market cap use market data.
About PROTHENA CORP PUBLIC LTD CO
Prothena Corporation plc is a clinical-stage biotechnology company that develops therapies targeting protein misfolding in neurodegenerative and rare peripheral amyloid diseases. Its pipeline includes treatments for Parkinson’s disease, ATTR amyloidosis with cardiomyopathy, Alzheimer’s disease, and ALS, using proprietary technologies such as CYTOPE® to target intracellular disease pathways. The company partners with large pharmaceutical firms to advance its clinical programs and focuses on diseases with unmet medical needs.
Snapshot
Fundamentals are from SEC filings for FY2025, the latest annual period (ended December 31, 2025). P/E and market cap are derived from stored market prices, last retrieved on a rolling basis and typically within the past week.
What changed at Prothena Corp Public
- Revenue fell 92.8% to $10M in FY2025, slower than the 47.9% the year before.
- Operating margin is now a 2216.4% loss in FY2025, from 35.9% in FY2021.
- Most recent quarter Q2 FY2026: revenue $1M, down 77.1% from Q2 FY2025.
- Net loss widened to $244M in FY2025, from $122M in FY2024.
Computed from the as-reported figures in the statements below. A change we cannot state from filed figures is left out rather than estimated.
Peer comparison
Where Prothena Corp Public’s fundamentals sit among the 198 pharmaceutical companies. Each figure is ranked only against peers that report it, from lowest (left) to highest (right).
Prothena Corp Public’s revenue growth of -92.8% ranks in the 5th percentile of the 187 pharmaceutical companies reporting it.
6 reported insider purchases (code P) totaling $2.4M in the last 90 days, against 2 sales totaling $135,974. For context, about 15% of companies in the universe saw any reported insider purchase (code P) in the same window. Browse insider activity →
Percentiles describe where a figure sits among industry peers reporting it (100th = highest). They are position within a peer group, not a rating, and not investment advice. Short interest ranking uses days to cover from FINRA Consolidated Short Interest data; FINRA is the owner and source of that data, included at no additional charge.
Recent insider activity
Non-derivative buys and sells (codes P/S) reported by officers, directors and 10% owners on SEC Form 4.
| Trade date | Insider | Type | Shares | Price | Value |
|---|---|---|---|---|---|
2026-08-20 filed 2026-08-21 | SCULLY WILLIAM P10% owner | Buy | 50.0K | $8.79 | $439K |
2026-08-07 filed 2026-08-10 | SCULLY WILLIAM P10% owner | Buy | 34.0K | $8.62 | $293K |
2026-08-07 filed 2026-08-10 | SCULLY WILLIAM P10% owner | Buy | 3.5K | $8.62 | $30K |
2026-07-29 filed 2026-07-30 | Isaacs Michael JohnGeneral Counsel & Company Sec. | Sell | 8.4K | $8.47 | $71K |
2026-07-29 filed 2026-07-30 | Kingston Anne EvansChief Strategy Officer | Sell | 7.7K | $8.47 | $65K |
2026-06-16 filed 2026-06-18 | SCULLY WILLIAM P10% owner | Buy | 20.0K | $7.90 | $158K |
2026-06-11 filed 2026-06-12 | SCULLY WILLIAM P10% owner | Buy | 125.0K | $8.17 | $1.0M |
2026-06-04 filed 2026-06-05 | SCULLY WILLIAM P10% owner | Buy | 50.0K | $9.31 | $465K |
2026-06-02 filed 2026-06-03 | SCULLY WILLIAM P10% owner | Buy | 50.0K | $9.43 | $471K |
2026-05-22 filed 2026-05-26 | SCULLY WILLIAM P10% owner | Buy | 100.0K | $9.81 | $981K |
Reported non-derivative purchases and sales (codes P/S) — which may be open-market or private; excludes option exercises, grants, and shares withheld for taxes. Dates shown are the trade date; a Form 4 can be filed days to years later. A sale can be routine (e.g. a pre-set 10b5-1 plan), so read individual transactions in context. From SEC Form 4. Not investment advice.
Short interest
Total shares sold short as of each twice-monthly FINRA settlement. Rising short interest means more investors are positioned against the stock; days to cover estimates how many trading days of average volume that position represents.
| Settlement | Shares short | Change | Days to cover |
|---|---|---|---|
| 2026-08-14 | 8.5M | +4.6% | 19.56 |
| 2026-07-31 | 8.2M | -0.3% | 13.96 |
| 2026-07-15 | 8.2M | -2.1% | 16.40 |
| 2026-06-30 | 8.4M | +6.4% | 11.02 |
| 2026-06-15 | 7.9M | +1.7% | 15.98 |
| 2026-05-29 | 7.7M | +9.0% | 13.85 |
| 2026-05-15 | 7.1M | +3.3% | 12.96 |
| 2026-04-30 | 6.9M | -2.9% | 18.33 |
Source: FINRA Consolidated Short Interest. FINRA is the owner and source of the FINRA-supplied data, which is included at no additional charge for your own personal or professional use; republishing or redistributing it is not permitted. Settlement dates are shown; FINRA publishes each settlement about nine business days later, so the latest figure can be two to four weeks old. Not presented as a percentage of float. No FINRA endorsement of this product is implied. Not investment advice.
Income statement (as reported)
| FY2025 | FY2024 | FY2023 | FY2022 | FY2021 | |
|---|---|---|---|---|---|
| Revenue | $9.7M | $135.2M | $91.4M | $53.9M | $200.6M |
| Gross profit | — | — | — | — | — |
| Operating income | $-214.6M | $-154.6M | $-191.0M | $-131.6M | $72.0M |
| Net income | $-244.1M | $-122.3M | $-147.0M | $-116.9M | $67.0M |
| Diluted EPS | $-4.53 | $-2.27 | $-2.76 | $-2.47 | $1.38 |
Figures as reported to the SEC. Underlined values link to the filing they came from; dotted values are calculated by us from reported figures; “adj” means restated for a stock split (hover to see the figure as filed). Full details: where the numbers come from.
Balance sheet (as reported)
| FY2025 | FY2024 | FY2023 | FY2022 | FY2021 | |
|---|---|---|---|---|---|
| Cash and equivalents | $307.5M | $471.4M | $618.8M | $710.4M | $579.1M |
| Current assets | $315.2M | $485.4M | $639.3M | $719.1M | $584.8M |
| Total assets | $326.8M | $547.1M | $696.4M | $758.0M | $609.4M |
| Current liabilities | $40.8M | $48.5M | $56.9M | $50.1M | $33.5M |
| Long-term debt | — | — | — | — | — |
| Total liabilities | $46.3M | $60.2M | $135.0M | $136.0M | $143.3M |
| Total equity | $280.5M | $486.9M | $561.4M | $622.0M | $466.0M |
Figures as reported to the SEC. Underlined values link to the filing they came from; dotted values are calculated by us from reported figures; “adj” means restated for a stock split (hover to see the figure as filed). Full details: where the numbers come from.
Cash flow (as reported)
| FY2025 | FY2024 | FY2023 | FY2022 | FY2021 | |
|---|---|---|---|---|---|
| Operating cash flow | $-163.6M | $-150.1M | $-133.9M | $-108.8M | $92.6M |
| Capital expenditure | — | — | — | — | — |
| Free cash flow | — | — | — | — | — |
Figures as reported to the SEC. Underlined values link to the filing they came from; dotted values are calculated by us from reported figures; “adj” means restated for a stock split (hover to see the figure as filed). Full details: where the numbers come from.
Quarterly trend (as reported)
| Quarter | Revenue | Revenue YoY | Net income | Diluted EPS |
|---|---|---|---|---|
| Q2 FY2026 | $1.0M | -77.1% | $-18.6M | $-0.36 |
| Q1 FY2026 | $51.1M | 1706.4% | $32.7M | $0.60 |
| Q4 FY2025 | $21,000 | -99.0% | $-21.6M | $-0.40 |
| Q3 FY2025 | $2.4M | 149.0% | $-36.5M | $-0.68 |
| Q2 FY2025 | $4.4M | -96.7% | $-125.8M | $-2.34 |
| Q1 FY2025 | $2.8M | 5556.0% | $-60.2M | $-1.12 |
| Q4 FY2024 | $2.1M | 571.8% | $-58.0M | $-1.08 |
| Q3 FY2024 | $970,000 | -98.9% | $-59.0M | $-1.10 |
Latest 8 reported quarters, from company XBRL filings on SEC EDGAR.
Company facts
Selected SEC filings
Largest pharmaceutical peers
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Data sourced from SEC EDGAR. Figures are as-reported and may be unaudited or restated; verify against the source filing before relying on them. Informational only. Not investment advice.