Revenue remains highly erratic due to milestone dependence, with operating margins swinging from -1630.6% in 2024Q1 to 50.5% in 2026Q1 as R&D spending continues to dominate the cost structure.
| Metric | TTM | Dec'25 | Dec'24 | Dec'23 | Dec'22 | Dec'21 | Dec'20 | Dec'19 | Dec'18 | Dec'17 | Dec'16 | Dec'15 | Dec'14 | Dec'13 | Dec'12 | Dec'11 | Dec'10 |
|---|
| Sales/Revenue | 57.94M | 9.68M | 135.16M | 91.37M | 53.91M | 200.58M | 853K | 814K | 955K | 27.52M | 1.05M | 1.61M | 50.85M | 676K | 2.66M | 507K | 1.24M |
| Revenue Growth % | -57.99% | -92.84% | 47.92% | 69.5% | -73.13% | 23414.3% | 4.79% | -14.76% | -96.53% | 2508.44% | -34.35% | -96.84% | 7422.78% | -74.57% | 424.26% | -59.21% | - |
| Cost of Goods Sold | 30.8M | 3.7M | 0 | 0 | 0 | 0 | 74.88M | 50.84M | 101.18M | 134.55M | 119.53M | 58.44M | 38.45M | 26.05M | 34.14M | 0 | 0 |
| COGS % of Revenue | - | 38.23% | - | - | - | - | 8778.9% | 6245.21% | 10595.08% | 488.92% | 11330.24% | 3636.53% | 75.61% | 3853.85% | 1284.39% | - | - |
| Gross Profit | 27.14M | 5.98M | 135.16M | 91.37M | 53.91M | 200.58M | -74.03M | -50.02M | -100.23M | -107.03M | -118.48M | -56.83M | 12.4M | -25.38M | -31.48M | 507K | 1.24M |
| Gross Margin % | 46.84% | 61.77% | 100% | 100% | 100% | 100% | -8678.9% | -6145.21% | -10495.08% | -388.92% | -11230.24% | -3536.53% | 24.39% | -3753.85% | -1184.39% | 100% | 100% |
| Gross Profit Growth % | - | -95.57% | 47.92% | 69.5% | -73.13% | 370.94% | -48% | 50.09% | 6.35% | 9.66% | -108.47% | -558.25% | 148.87% | 19.39% | -6309.27% | -59.21% | - |
| Operating Expenses | 153.42M | 190.54M | 289.72M | 282.41M | 185.46M | 128.6M | 38.7M | 35.67M | 143.66M | 182.77M | 160.59M | 81.54M | 57.5M | 41.1M | 44.07M | 29.75M | 13.4M |
| OpEx % of Revenue | - | 1967.6% | 214.36% | 309.08% | 344.05% | 64.12% | 4537.28% | 4382.68% | 15043.46% | 664.17% | 15221.8% | 5074.3% | 113.07% | 6080.33% | 1657.94% | 5868.05% | 1078.44% |
| Selling, General & Admin | 54.46M | 59.39M | 67.2M | 61.84M | 49.9M | 46.32M | 38.7M | 35.74M | 42.48M | 48.23M | 41.06M | 23.11M | 19.05M | 15.05M | 9.93M | 5.58M | 3.62M |
| SG&A % of Revenue | - | 613.3% | 49.72% | 67.68% | 92.57% | 23.09% | 4537.28% | 4390.17% | 4448.38% | 175.25% | 3891.56% | 1437.77% | 37.46% | 2226.48% | 373.55% | 1100.39% | 291.07% |
| Research & Development | 96.67M | 134.85M | 222.52M | 220.57M | 135.56M | 82.28M | 75.09M | 50.84M | 101.18M | 134.55M | 119.53M | 58.44M | 38.45M | 26.05M | 34.14M | 24.17M | 9.79M |
| R&D % of Revenue | - | 1392.52% | 164.64% | 241.4% | 251.48% | 41.02% | 8803.4% | 6245.21% | 10595.08% | 488.92% | 11330.24% | 3636.53% | 75.61% | 3853.85% | 1284.39% | 4767.65% | 787.37% |
| Other Operating Expenses | -1.86M | -3.7M | 0 | 0 | 0 | 0 | -75.09M | -50.9M | 2.74M | -2.35M | 571K | 26K | 310K | -225K | 0 | 0 | 0 |
| Operating Income | -126.28M | -184.56M | -154.56M | -191.04M | -131.56M | 71.97M | -112.73M | -85.7M | -158.85M | -155.25M | -159.53M | -79.94M | -6.65M | -40.43M | -41.41M | -29.24M | -12.16M |
| Operating Margin % | -217.94% | -1905.82% | -114.36% | -209.08% | -244.05% | 35.88% | -13216.18% | -10527.89% | -16634.03% | -564.17% | -15121.8% | -4974.3% | -13.07% | -5980.33% | -1557.94% | -5768.05% | -978.44% |
| Operating Income Growth % | - | -19.41% | 19.09% | -45.21% | -282.78% | 163.84% | -31.55% | 46.05% | -2.32% | 2.68% | -99.58% | -1102.24% | 83.55% | 2.37% | -41.6% | -140.45% | - |
| EBITDA | -123.96M | -180.86M | -153.67M | -190.11M | -130.81M | 73.09M | -111.22M | -84.13M | -155.64M | -152.19M | -157.11M | -79.13M | -5.91M | -39.77M | -40.94M | -28.85M | -11.97M |
| EBITDA Margin % | -213.95% | -1867.6% | -113.7% | -208.06% | -242.67% | 36.44% | -13038.69% | -10335.75% | -16297.28% | -553.03% | -14891.75% | -4924.14% | -11.61% | -5882.69% | -1540.33% | -5690.93% | -963.07% |
| EBITDA Growth % | 9.99% | -17.69% | 19.17% | -45.33% | -278.98% | 165.72% | -32.2% | 45.94% | -2.27% | 3.13% | -98.54% | -1239.84% | 85.15% | 2.87% | -41.9% | -141.02% | - |
| D&A (Non-Cash Add-back) | 2.31M | 3.7M | 893K | 928K | 744K | 1.11M | 1.51M | 1.56M | 3.22M | 3.07M | 2.43M | 806K | 743K | 660K | 468K | 391K | 191K |
| EBIT | -83.97M | -200.83M | -154.56M | -191.04M | -131.56M | 71.97M | -112.73M | -85.76M | -152.42M | -153.91M | -158.96M | -79.94M | -6.65M | -40.43M | -41.41M | -29.24M | -12.16M |
| Net Interest Income | 12.21M | 14.14M | 25.82M | 31.01M | 6.35M | 42K | 1.37M | 8.2M | 2.69M | -142K | 556K | 196K | 79K | 71K | 5K | 0 | 0 |
| Interest Income | 12.21M | 14.14M | 25.82M | 31.01M | 6.35M | 42K | 1.37M | 8.2M | 6.39M | 3.55M | 1.42M | 196K | 79K | 71K | 5K | 0 | 0 |
| Interest Expense | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3.7M | 3.69M | 863K | 0 | 0 | 0 | 0 | 0 | 0 |
| Other Income/Expense | 20.28M | -16.27M | 25.63M | 30.56M | 5.95M | -54K | 1.87M | 8.4M | 2.74M | -2.35M | 571K | 26K | 310K | -154K | 5K | 0 | 0 |
| Pretax Income | -105.99M | -200.83M | -128.93M | -160.48M | -125.61M | 71.92M | -110.86M | -77.3M | -156.12M | -157.6M | -158.96M | -79.91M | -6.34M | -40.58M | -41.41M | -29.24M | -12.16M |
| Pretax Margin % | -182.93% | -2073.82% | -95.39% | -175.64% | -233.01% | 35.86% | -12996.6% | -9496.07% | -16347.12% | -572.71% | -15067.68% | -4972.68% | -12.47% | -6003.11% | -1557.75% | -5768.05% | -978.44% |
| Income Tax | 45.18M | 43.26M | -6.62M | -13.45M | -8.66M | 4.95M | 283K | 379K | -470K | -4.37M | 1.14M | 701K | 811K | 415K | 6K | 426K | 320K |
| Effective Tax Rate % | -42.63% | -21.54% | 5.13% | 8.38% | 6.89% | 6.88% | -0.26% | -0.49% | 0.3% | 2.77% | -0.72% | -0.88% | -12.79% | -1.02% | -0.01% | -1.46% | -2.63% |
| Net Income | -151.18M | -244.09M | -122.31M | -147.03M | -116.95M | 66.97M | -111.14M | -77.68M | -155.65M | -153.24M | -160.11M | -80.61M | -7.15M | -41M | -41.41M | -29.67M | -12.48M |
| Net Margin % | -260.92% | -2520.57% | -90.49% | -160.92% | -216.95% | 33.39% | -13029.78% | -9542.63% | -16297.91% | -556.84% | -15176.11% | -5016.3% | -14.06% | -6064.5% | -1557.98% | -5852.07% | -1004.18% |
| Net Income Growth % | -37.1% | -99.57% | 16.81% | -25.72% | -274.62% | 160.26% | -43.08% | 50.09% | -1.57% | 4.29% | -98.62% | -1027.44% | 82.56% | 1% | -39.57% | -137.7% | - |
| Net Income (Continuing) | -151.18M | -244.09M | -122.31M | -147.03M | -116.95M | 66.97M | -111.14M | -77.68M | -155.65M | -153.24M | -160.11M | -80.61M | -7.15M | -41M | -41.41M | -29.67M | -12.48M |
| Discontinued Operations | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Minority Interest | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| EPS (Diluted) | -2.79 | -4.53 | -2.27 | -2.76 | -2.47 | 1.38 | -2.78 | -1.95 | -3.93 | -4.07 | -4.66 | -2.66 | -0.29 | -2.20 | -2.84 | -1.68 | -0.71 |
| EPS Growth % | -35.58% | -99.56% | 17.75% | -11.74% | -278.99% | 149.64% | -42.56% | 50.38% | 3.44% | 12.66% | -75.19% | -817.24% | 86.82% | 22.54% | -69.05% | -136.62% | - |
| EPS (Basic) | - | -4.53 | -2.27 | -2.76 | -2.47 | 1.51 | -2.78 | -1.95 | -3.93 | -4.07 | -4.66 | -2.66 | -0.29 | -2.20 | -2.84 | -1.68 | -0.71 |
| Diluted Shares Outstanding | 54.11M | 53.83M | 53.77M | 53.22M | 47.37M | 48.46M | 39.91M | 39.88M | 39.56M | 37.65M | 34.35M | 30.33M | 24.67M | 18.61M | 14.59M | 17.68M | 17.68M |
| Basic Shares Outstanding | 53.71M | 53.83M | 53.77M | 53.22M | 47.37M | 44.23M | 39.91M | 39.88M | 39.56M | 37.65M | 34.35M | 30.33M | 24.67M | 18.61M | 14.59M | 17.68M | 17.68M |
| Dividend Payout Ratio | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
Clinical milestone dependency
As reported in recent financial statements, Prothena's revenue profile remains highly erratic, evidenced by a 92.84% year-over-year decline in certain periods, which underscores the company's reliance on non-recurring milestone payments from strategic partners rather than consistent, organic commercial product sales or recurring service-based income streams.
The revenue trajectory is fundamentally tied to the timing of clinical trial milestones rather than market-driven demand. Investors should monitor the remaining performance obligations, as the current lack of a commercialized asset makes top-line growth inherently unpredictable and susceptible to significant quarterly fluctuations.
Based on the company's reported figures, R&D spending remains the primary driver of the cost structure, consistently consuming the majority of operating resources as the firm advances its pipeline, which suggests that expense discipline is currently secondary to the urgent necessity of clinical trial execution.
The high concentration of costs in R&D highlights the pre-commercial nature of the business model. Management's ability to control these expenditures is limited by the regulatory requirements of late-stage trials, implying that operating losses will likely persist until a successful product launch alters the cost-to-revenue ratio.
According to the provided income statement data, Prothena lacks meaningful operating leverage, as the company's operating income frequently swings into deep negative territory, reflecting a business model that has yet to achieve the scale necessary to offset its substantial fixed overhead and research-related expenditures.
The absence of a stable revenue base prevents the realization of economies of scale, leaving the operating margin highly sensitive to the timing of partnership inflows. This structure suggests that the company remains in a high-risk phase where operating efficiency is secondary to the successful validation of its therapeutic pipeline.
Analysis of the income statement suggests that the occasional positive net income, such as the $32.7 million reported in 2026Q1, may be an accounting anomaly driven by milestone recognition rather than a sustainable shift toward profitability, warranting further investigation into the underlying cash-generating capacity of the business.
Short-sellers would likely focus on the disconnect between these periodic accounting profits and the underlying cash burn required to sustain operations. The reliance on non-recurring items masks the structural reality that the company has not yet demonstrated a repeatable, self-funding business model.
Quick answers to the most common questions about buying PRTA stock.
For fiscal year 2025, Prothena Corporation plc (PRTA) reported total revenue of $9.7M. This represents a 679.1% increase compared to $1.2M in 2010.
Prothena Corporation plc (PRTA) reported a net loss of $244.1M for the fiscal year ending 2025.
Prothena Corporation plc (PRTA) reported an operating income of $-184.6M, resulting in an operating profit margin of -1905.8%. This margin reflects the operational efficiency of the business before interest and taxes.
Prothena Corporation plc (PRTA) generated $6.0M in gross profit for the year, representing a gross profit margin of 61.8%. This demonstrates the company's core pricing power and production efficiency.