Tearsheet

Prothena (PRTA)


Market Price (12/29/2025): $9.535 | Market Cap: $513.3 Mil
Sector: Health Care | Industry: Biotechnology

Prothena (PRTA)


Market Price (12/29/2025): $9.535
Market Cap: $513.3 Mil
Sector: Health Care
Industry: Biotechnology

Investment Highlights Why It Matters Detailed financial logic regarding cash flow yields vs trend-riding momentum.


0 Cash is significant % of market cap
Net D/ENet Debt/Equity. Debt net of cash. Negative indicates net cash. Equity is taken as the Market Capitalization is -63%
Weak multi-year price returns
2Y Excs Rtn is -120%, 3Y Excs Rtn is -165%
Not profitable at operating income level
Op Inc LTMOperating Income, Last Twelve Months is -222 Mil, Op Mgn LTMOperating Margin = Operating Income / Revenue Reflects profitability before taxes and before impact of capital structure (interest payments). is -1886%
1 Megatrend and thematic drivers
Megatrends include Precision Medicine, and Aging Population & Chronic Disease. Themes include Targeted Therapies, Biopharmaceutical R&D, Show more.
  Weak revenue growth
Rev Chg LTMRevenue Change % Last Twelve Months (LTM) is -91%
2   Significant share based compensation
SBC/Rev LTMShare Based Compensation / Revenue (Sales), Last Twelve Months (LTM) is 349%
3   Not cash flow generative
CFO/Rev LTMCash Flow from Operations / Revenue (Sales), Last Twelve Months (LTM) is -1595%, FCF/Rev LTMFree Cash Flow / Revenue (Sales), Last Twelve Months (LTM) is -1597%
4   Yield minus risk free rate is negative
ERPEquity Risk Premium (ERP) = Total Yield - Risk Free Rate, Reflects the premium above risk free assets offered by the investment. is -59%
5   Key risks
PRTA key risks include [1] a heavy dependence on its narrowed pipeline of high-risk neurodegenerative candidates following the Phase 3 failure of its former lead candidate, Show more.
0 Cash is significant % of market cap
Net D/ENet Debt/Equity. Debt net of cash. Negative indicates net cash. Equity is taken as the Market Capitalization is -63%
1 Megatrend and thematic drivers
Megatrends include Precision Medicine, and Aging Population & Chronic Disease. Themes include Targeted Therapies, Biopharmaceutical R&D, Show more.
2 Weak multi-year price returns
2Y Excs Rtn is -120%, 3Y Excs Rtn is -165%
3 Not profitable at operating income level
Op Inc LTMOperating Income, Last Twelve Months is -222 Mil, Op Mgn LTMOperating Margin = Operating Income / Revenue Reflects profitability before taxes and before impact of capital structure (interest payments). is -1886%
4 Weak revenue growth
Rev Chg LTMRevenue Change % Last Twelve Months (LTM) is -91%
5 Significant share based compensation
SBC/Rev LTMShare Based Compensation / Revenue (Sales), Last Twelve Months (LTM) is 349%
6 Not cash flow generative
CFO/Rev LTMCash Flow from Operations / Revenue (Sales), Last Twelve Months (LTM) is -1595%, FCF/Rev LTMFree Cash Flow / Revenue (Sales), Last Twelve Months (LTM) is -1597%
7 Yield minus risk free rate is negative
ERPEquity Risk Premium (ERP) = Total Yield - Risk Free Rate, Reflects the premium above risk free assets offered by the investment. is -59%
8 Key risks
PRTA key risks include [1] a heavy dependence on its narrowed pipeline of high-risk neurodegenerative candidates following the Phase 3 failure of its former lead candidate, Show more.

Valuation, Metrics & Events

PRTA Stock


Why The Stock Moved


Qualitative Assessment

AI Analysis | Feedback

Here are the key points highlighting why Prothena (PRTA) stock moved by 16.3% for the approximate time period from August 31, 2025, to December 29, 2025:

1. Advancement of Prasinezumab into Phase 3 Clinical Trial. Roche, Prothena's partner, announced its plan to initiate the Phase 3 PARAISO clinical trial evaluating prasinezumab, a potential first-in-class anti-alpha-synuclein antibody, for early-stage Parkinson's disease by the end of 2025. Roche has indicated that prasinezumab has a peak sales potential exceeding $3.5 billion, highlighting its significant market opportunity.

2. Initiation of Phase 3 Development for Coramitug. Novo Nordisk, another partner, initiated the Phase 3 CLEOPATTRA clinical trial to evaluate coramitug (formerly PRX004), a potential first-in-class amyloid depleter, for ATTR amyloidosis with cardiomyopathy. This advancement into late-stage development underscores the potential of this therapeutic candidate.

Show more

Stock Movement Drivers

Fundamental Drivers

The 1.4% change in PRTA stock from 9/28/2025 to 12/28/2025 was primarily driven by a 14.0% change in the company's Total Revenues ($ Mil).
928202512282025Change
Stock Price ($)9.419.541.38%
Change Contribution ByLTMLTM
Total Revenues ($ Mil)10.3411.7913.97%
P/S Multiple48.9843.57-11.04%
Shares Outstanding (Mil)53.8353.83-0.01%
Cumulative Contribution1.38%

LTM = Last Twelve Months as of date shown

Market Drivers

9/28/2025 to 12/28/2025
ReturnCorrelation
PRTA1.4% 
Market (SPY)4.3%39.6%
Sector (XLV)15.2%23.4%

Fundamental Drivers

The 56.9% change in PRTA stock from 6/29/2025 to 12/28/2025 was primarily driven by a 1736.4% change in the company's P/S Multiple.
629202512282025Change
Stock Price ($)6.089.5456.91%
Change Contribution ByLTMLTM
Total Revenues ($ Mil)137.9411.79-91.46%
P/S Multiple2.3743.571736.44%
Shares Outstanding (Mil)53.8353.83-0.01%
Cumulative Contribution56.91%

LTM = Last Twelve Months as of date shown

Market Drivers

6/29/2025 to 12/28/2025
ReturnCorrelation
PRTA56.9% 
Market (SPY)12.6%29.9%
Sector (XLV)17.0%19.6%

Fundamental Drivers

The -37.0% change in PRTA stock from 12/28/2024 to 12/28/2025 was primarily driven by a -91.2% change in the company's Total Revenues ($ Mil).
1228202412282025Change
Stock Price ($)15.149.54-36.99%
Change Contribution ByLTMLTM
Total Revenues ($ Mil)133.3511.79-91.16%
P/S Multiple6.1143.57613.46%
Shares Outstanding (Mil)53.7953.83-0.07%
Cumulative Contribution-36.99%

LTM = Last Twelve Months as of date shown

Market Drivers

12/28/2024 to 12/28/2025
ReturnCorrelation
PRTA-37.0% 
Market (SPY)17.0%16.8%
Sector (XLV)13.8%20.7%

Fundamental Drivers

The -84.0% change in PRTA stock from 12/29/2022 to 12/28/2025 was primarily driven by a -92.0% change in the company's P/S Multiple.
1229202212282025Change
Stock Price ($)59.689.54-84.01%
Change Contribution ByLTMLTM
Total Revenues ($ Mil)5.1511.79128.68%
P/S Multiple544.0743.57-91.99%
Shares Outstanding (Mil)46.9953.83-14.57%
Cumulative Contribution-84.35%

LTM = Last Twelve Months as of date shown

Market Drivers

12/29/2023 to 12/28/2025
ReturnCorrelation
PRTA-73.7% 
Market (SPY)48.4%20.8%
Sector (XLV)17.8%22.2%

Return vs. Risk


Price Returns Compared

 202020212022202320242025Total [1]
Returns
PRTA Return-24%311%22%-40%-62%-30%-39%
Peers Return16%38%-12%21%26%16%150%
S&P 500 Return16%27%-19%24%23%18%114%

Monthly Win Rates [3]
PRTA Win Rate58%58%50%42%25%58% 
Peers Win Rate52%65%42%68%57%52% 
S&P 500 Win Rate58%75%42%67%75%73% 

Max Drawdowns [4]
PRTA Max Drawdown-52%-8%-54%-46%-67%-67% 
Peers Max Drawdown-34%-5%-26%-7%-9%-23% 
S&P 500 Max Drawdown-31%-1%-25%-1%-2%-15% 


[1] Cumulative total returns since the beginning of 2020
[2] Peers: HPQ, HPE, IBM, CSCO, AAPL. See PRTA Returns vs. Peers.
[3] Win Rate = % of calendar months in which monthly returns were positive
[4] Max drawdown represents maximum peak-to-trough decline within a year
[5] 2025 data is for the year up to 12/26/2025 (YTD)

How Low Can It Go

Unique KeyEventPRTAS&P 500
2022 Inflation Shock2022 Inflation Shock  
2022 Inflation Shock% Loss% Loss-71.2%-25.4%
2022 Inflation Shock% Gain to Breakeven% Gain to Breakeven247.1%34.1%
2022 Inflation ShockTime to BreakevenTime to BreakevenNot Fully Recovered days464 days
2020 Covid Pandemic2020 Covid Pandemic  
2020 Covid Pandemic% Loss% Loss-52.4%-33.9%
2020 Covid Pandemic% Gain to Breakeven% Gain to Breakeven109.9%51.3%
2020 Covid PandemicTime to BreakevenTime to Breakeven331 days148 days
2018 Correction2018 Correction  
2018 Correction% Loss% Loss-89.8%-19.8%
2018 Correction% Gain to Breakeven% Gain to Breakeven883.3%24.7%
2018 CorrectionTime to BreakevenTime to Breakeven735 days120 days

Compare to HPQ, HPE, IBM, CSCO, AAPL

In The Past

Prothena's stock fell -71.2% during the 2022 Inflation Shock from a high on 9/23/2021. A -71.2% loss requires a 247.1% gain to breakeven.

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About Prothena (PRTA)

Prothena Corporation plc, a late-stage clinical company, focuses on discovery and development of novel therapies for life-threatening diseases in the United States. The company is involved in developing Birtamimab, an investigational humanized antibody that is in Phase III clinical trial for the treatment of AL amyloidosis; Prasinezumab, a humanized monoclonal antibody, which is in Phase IIb clinical trial for the treatment of Parkinson's disease; PRX004 that completed Phase I clinical trial for the treatment of Transthyretin amyloidosis; and PRX005, which is in Phase I clinical trial for the treatment of Alzheimer's disease. Its discovery and preclinical programs include PRX012 for the treatment of Alzheimer's disease; and dual Aß-Tau vaccine for the treatment and prevention of Alzheimer's disease. Prothena Corporation plc has a license, development, and commercialization agreement with F. Hoffmann-La Roche Ltd. and Hoffmann-La Roche Inc. to develop and commercialize antibodies that target alpha-synuclein; and a collaboration agreement with Bristol-Myers Squibb to develop antibodies. The company was founded in 2012 and is based in Dublin, Ireland.

AI Analysis | Feedback

Here are 1-3 brief analogies for Prothena:

  • Prothena is like a Biogen or Eli Lilly, but intensely focused on developing antibody therapies for neurodegenerative diseases like Alzheimer's and Parkinson's.
  • Think of Prothena as a specialized biotech company like Biogen or Eli Lilly, dedicated to finding novel immunotherapies for devastating neurodegenerative and amyloid diseases.
  • A biotech akin to Biogen or Eli Lilly, but with a laser focus on developing treatments that clear the misfolded proteins driving diseases like Alzheimer's and Parkinson's.

AI Analysis | Feedback

  • Birtamimab: An investigational antibody designed to clear amyloid fibrils in patients with AL amyloidosis, currently in a Phase 3 clinical trial.
  • PRX012: An investigational antibody targeting amyloid-beta (Aβ) for the potential treatment of Alzheimer's disease, currently in a Phase 1 clinical trial.
  • PRX005 (co-developed with Roche): An investigational antibody targeting alpha-synuclein for the treatment of Parkinson's disease, currently in a Phase 2 clinical trial.
  • PRX004 (licensed to Novo Nordisk): An investigational antibody targeting transthyretin (TTR) for the treatment of ATTR amyloidosis, currently in a Phase 2 clinical trial.

AI Analysis | Feedback

Prothena (PRTA) is a biotechnology company that primarily sells to other companies, specifically larger pharmaceutical companies, through collaboration and licensing agreements for its therapeutic candidates.

Based on its most recent financial disclosures (fiscal year 2023), its major customer was:

  • Bristol Myers Squibb (Symbol: BMS)

Historically, another significant customer and collaborator was:

  • Roche Holding AG (Symbol: RHHBY - for American Depositary Receipts) - While a major partner for several years and contributing substantially to Prothena's revenue, the collaboration agreement for prasinezumab was terminated by Roche in late 2023.

AI Analysis | Feedback

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Gene G. Kinney, Ph.D. President and Chief Executive Officer

Dr. Gene G. Kinney has served as President and Chief Executive Officer of Prothena since 2016, and he has been a member of the company's Board of Directors since September 2016. He was a founding member of Prothena's leadership team, initially serving as Chief Scientific Officer and Head of Research and Development from 2012 to 2016, and then as Chief Operating Officer for part of 2016. Before joining Prothena, Dr. Kinney held various positions at Elan Pharmaceuticals Inc. from 2009 to 2012, including Vice President of Pharmacology and Senior Vice President of Pharmacological Sciences, where he also served as Head of Nonclinical Research for Janssen Alzheimer Immunotherapy R&D. Prior to that, from 2001 to 2009, he was Senior Director, Head of Central Pharmacology at Merck Research Laboratories. He also held positions at Bristol Myers Squibb and was an Assistant Professor at Emory University School of Medicine. Dr. Kinney also serves as Chairman at Libra Therapeutics, Inc.

Tran B. Nguyen Chief Strategy Officer and Chief Financial Officer

Mr. Tran B. Nguyen has served as Chief Strategy Officer since September 2021 and Chief Financial Officer since 2013. He also served as Chief Operating Officer from June 2018 to September 2021. Mr. Nguyen brings over 25 years of finance experience from the biotechnology, banking, and private equity industries. Before joining Prothena in 2013, he was Chief Financial Officer at Somaxon Pharmaceuticals, Inc. until its sale in 2013. Previously, Mr. Nguyen served as Vice President and Chief Financial Officer at Metabasis Therapeutics, Inc. until its sale in 2010. His background also includes roles as Vice President in the Healthcare Investment Banking group at Citi Global Markets, Inc. (2007-2009) and various healthcare investment banking capacities at Lehman Brothers, Inc. (2004-2007). Mr. Nguyen has also served on the board of directors for Sierra Oncology, Inc. and Rain Therapeutics Inc.

Brandon Smith Chief Operating Officer

Mr. Brandon Smith has served as Chief Operating Officer of Prothena since September 2021. Prior to this, he was the Chief Business Officer from March 2020 through September 2021. Before joining Prothena in 2020, Mr. Smith was the Chief Operating Officer at Iconic Therapeutics, Inc., a biopharmaceutical company, from 2017 to 2020. From 2012 to 2017, he held senior leadership positions at Impax Laboratories, LLC, including Senior Vice President and Vice President of Corporate Development and Strategy. Mr. Smith also spent seven years at Amgen Inc. (2005-2012) in roles such as Executive Director, Biosimilars Strategy, and Director, Strategy and Corporate Development. He began his career as a Consultant and Project Leader at The Boston Consulting Group.

Chad J. Swanson, Ph.D. Chief Development Officer

Dr. Chad J. Swanson was appointed Chief Development Officer in September 2024, after joining Prothena in January 2023 as Senior Vice President and Head of Clinical Development. He is a neuropharmacologist with over two decades of industry experience. Prior to Prothena, Dr. Swanson served as Executive Director of Clinical Research in the Alzheimer's Disease Brain Health group at Eisai, Inc. During his 11-year tenure at Eisai, he was the International Project Team Leader responsible for the lecanemab program, where he successfully delivered a Phase 2 dose-finding study that established proof of concept for the treatment of early Alzheimer's disease.

AI Analysis | Feedback

Key Risks to Prothena (PRTA)

  1. Clinical Trial Failures and Pipeline Dependence: As a late-stage clinical biotechnology company, Prothena's business success is heavily dependent on the successful development and approval of its investigational therapies. The discontinuation of its lead candidate, birtamimab, following a Phase 3 trial failure, underscores this significant risk. This has led to a narrowed pipeline and increased reliance on the success of other candidates, such as PRX012 for Alzheimer's disease and prasinezumab for Parkinson's disease. The development of treatments for neurodegenerative diseases like Alzheimer's is particularly challenging, with a historically high failure rate in clinical trials, posing substantial clinical and regulatory risks for Prothena's future prospects.
  2. Unprofitability and Need for Additional Capital: Prothena is currently an unprofitable company with negative free cash flow, typical for a biotechnology firm in its development phase. While the company has reported a strong cash position, it anticipates requiring additional capital to fund ongoing research and development, and eventual commercialization of its drug candidates. Its financial trajectory hinges on clinical validation and operational execution, and the significant investment in R&D means a continued reliance on external funding or successful partnerships to sustain operations.
  3. Partnership and Regulatory Risks: Prothena's pipeline includes both wholly-owned and partnered programs, with collaborations such as the one with Roche for prasinezumab. There is an inherent risk that a partner could choose to terminate a collaboration at any time, which would significantly impact Prothena's resources and development timelines. Furthermore, advancing drug candidates requires navigating complex regulatory landscapes, and there is no guarantee that regulatory authorities, such as the FDA, will allow drugs to proceed through clinical stages or grant marketing approvals.

AI Analysis | Feedback

The success and market entry of anti-amyloid antibodies like Leqembi (lecanemab) from Eisai/Biogen and Donanemab from Eli Lilly in treating early Alzheimer's disease present a clear emerging threat to Prothena's PRX012 program. These approved and near-approved therapies are rapidly establishing a new standard of care for amyloid-targeting treatments in Alzheimer's disease. As PRX012 is still in Phase 1 development, it faces the challenge of demonstrating significantly superior efficacy, safety, or administration convenience to effectively compete against these validated and commercially available treatments that are setting the new market benchmark.

AI Analysis | Feedback

Prothena (PRTA) is a clinical-stage biotechnology company focused on developing novel therapies for neurodegenerative and rare peripheral amyloid diseases. The addressable market sizes for their main product candidates and programs are detailed below:

Parkinson's Disease (Prasinezumab - PRX002)

Prothena is evaluating prasinezumab, a humanized monoclonal antibody, in collaboration with Roche for the treatment of Parkinson's disease and other related synucleinopathies. Roche anticipates peak sales potential exceeding $3.5 billion (unadjusted) for prasinezumab.

  • Global Market: The global Parkinson's Disease Drugs Market is projected to reach USD 5.76 billion in 2025 and grow to USD 6.87 billion by 2030. Other estimates place the global Parkinson's disease therapeutics market at USD 6.59 billion in 2024, increasing to approximately USD 13.34 billion by 2034. The market is also expected to grow from USD 6.42 billion in 2024 to approximately US$ 11.28 billion by 2034.
  • U.S. Market: The U.S. Parkinson's disease therapeutics market was valued at USD 2.15 billion in 2024 and is predicted to be worth around USD 4.25 billion by 2034.

ATTR Amyloidosis (Coramitug - formerly PRX004)

Prothena's former candidate, Coramitug (PRX004), for ATTR amyloidosis, is now fully licensed to Novo Nordisk, with Prothena eligible for royalties. Novo Nordisk expects to advance Coramitug into a Phase III program for ATTR amyloidosis with cardiomyopathy (ATTR-CM) in 2025.

  • Global Market: The global ATTR amyloidosis treatment market is estimated to be valued at USD 4.14 billion in 2025 and is expected to reach USD 7.52 billion by 2032. Another report values the global transthyretin amyloidosis treatment market at USD 6.94 billion in 2024, with a projection to reach USD 20.35 billion by 2033. The transthyretin amyloidosis treatment market size is estimated at USD 6.12 billion in 2025, and is expected to reach USD 12.52 billion by 2030.
  • Regional Market: North America holds the largest market share for transthyretin amyloidosis treatment, at 46.3% in 2024. The United States accounted for the highest hereditary transthyretin amyloidosis treatment market size in the top 7 markets (US, EU4, UK, and Japan) in 2024.

Alzheimer's Disease (PRX012, PRX123, PRX019)

Prothena is heavily focused on its Alzheimer's disease pipeline, particularly PRX012, an experimental Alzheimer's therapy targeting amyloid beta, which analysts assign a 30% probability of success and potential approval by 2027. PRX012 has a potential for multi-billion-dollar peak sales. The company also has PRX123 (a dual Aβ and Tau vaccine) and PRX019 (an anti-Tau antibody) in its pipeline for Alzheimer's and neurodegenerative diseases.

  • Global Market: The global Alzheimer's drug market size is calculated at USD 4.18 billion in 2025 and is forecasted to reach approximately USD 7.13 billion by 2034. The global Alzheimer's therapeutics market size was valued at USD 5.8 billion in 2023 and is expected to exhibit growth at a CAGR of 9.8% from 2024 to 2032. The Alzheimer's disease market is expected to grow from $2.4 billion in 2023 to $19.3 billion by 2033 across the eight major markets (US, France, Germany, Italy, Spain, UK, Japan, and China).
  • U.S. Market: The North American Alzheimer's drug market is expected to dominate, holding a 47% share in 2024. The U.S. Alzheimer's drug market size was USD 1.48 billion in 2024 and is projected to be around USD 2.73 billion by 2034.

AL Amyloidosis (Birtamimab)

Prothena discontinued the development of birtamimab for AL amyloidosis following disappointing Phase 3 results in August 2025.

  • Global Market (for context, as the program is discontinued): The global AL amyloidosis market size was valued at $3.11 billion in 2024, projected to reach $3.52 billion in 2025, and grow to $5.74 billion by 2029. Other estimates include a global AL amyloidosis therapeutics market value of USD 2.59 billion in 2025, reaching USD 5.24 billion by 2035.
  • Regional Market (for context): The AL amyloidosis market across the top 7 markets (US, EU4, UK, and Japan) reached USD 3,816.6 Million in 2024 and is expected to reach USD 15,003.3 Million by 2035.

AI Analysis | Feedback

Prothena (PRTA) is poised for potential revenue growth over the next 2-3 years, primarily driven by the advancement of its diversified and partnered clinical pipeline. Key drivers include significant milestone payments and future royalties from its collaborations with major pharmaceutical companies.

  1. Advancement of Prasinezumab with Roche for Parkinson's Disease: Roche, Prothena's partner, is expected to initiate the late-stage PARAISO study for prasinezumab in early-stage Parkinson's disease by the end of 2025. This collaboration has a reported peak sales potential exceeding $3.5 billion, and successful progression will trigger milestone payments and future royalties for Prothena.

  2. Progression of Coramitug (formerly PRX004) with Novo Nordisk for ATTR Amyloidosis: Novo Nordisk acquired Coramitug and has initiated the late-stage CLEOPATTRA study for ATTR amyloidosis with cardiomyopathy. Prothena anticipates earning a clinical milestone payment when specific enrollment criteria are met in this ongoing Phase 3 study.

  3. Milestone Payments and Royalties from Bristol Myers Squibb Partnerships: Prothena's collaboration with Bristol Myers Squibb (BMS) for neurodegenerative diseases represents a significant revenue driver. This includes BMS-986446 (formerly PRX005), an antibody targeting tau for Alzheimer's disease, which received Fast Track Designation from the FDA in October 2025 and is in a Phase 2 trial. Additionally, Prothena initiated a Phase 1 clinical trial for PRX019 for neurodegeneration in 2025, with a clinical milestone expected by the end of 2026 if BMS decides to develop it further.

  4. Potential New Partnerships and Out-licensing of Wholly-Owned Programs: Prothena aims to generate revenue through strategic partnerships and out-licensing of its wholly-owned pipeline assets. For example, the company plans to explore partnership interest to further develop PRX012 and its preclinical PRX012-TfR antibody for Alzheimer's disease. Successful execution of such partnerships would bring in upfront payments, milestone payments, and potential royalties.

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Share Repurchases

  • Prothena is convening an Extraordinary General Meeting (EGM) on November 19, 2025, to seek shareholder approval for a reduction in share capital to create distributable reserves.
  • This capital reduction is intended to support a potential share redemption program in 2026, if deemed appropriate by the Board of Directors.

Share Issuance

  • As of October 31, 2025, Prothena had approximately 53.8 million ordinary shares outstanding.
  • The company projects approximately $41 million in non-cash share-based compensation expense for the full year 2025.
  • Shareholders authorized the Board in May 2022 to issue ordinary shares up to the amount of authorized share capital and to opt out of the statutory pre-emption right for such issuances.

Inbound Investments

  • Bristol Myers Squibb obtained an exclusive global license for PRX019 for $80 million, with Prothena eligible for up to $617.5 million in additional milestone payments and tiered royalties.
  • Novo Nordisk acquired Prothena's ATTR amyloidosis business and pipeline, including Coramitug (PRX004), for up to $1.2 billion.
  • Prothena is eligible to earn up to $105 million in aggregate clinical milestone payments by the end of 2026 related to the advancement of coramitug by Novo Nordisk and PRX019 by Bristol Myers Squibb.

Capital Expenditures

  • Prothena's historical capital expenditures were $0 million in 2020, $1 million in 2021, $0 million in 2022, $3 million in 2023, and $0 million in 2024.
  • Projected capital expenditures are $5 million for 2025, $6 million for 2026, $8 million for 2027, $10 million for 2028, and $12 million for 2029.
  • The estimated full year 2025 net cash used in operating and investing activities is expected to be $170 million to $178 million, primarily driven by R&D investments.

Better Bets than Prothena (PRTA)

Trade Ideas

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Unique KeyDateTickerCompanyCategoryTrade Strategy6M Fwd Rtn12M Fwd Rtn12M Max DD
CRL_11142025_Dip_Buyer_FCFYield11142025CRLCharles River Laboratories InternationalDip BuyDB | FCFY OPMDip Buy with High FCF Yield and High Margin
Buying dips for companies with high FCF yield and meaningfully high operating margin
21.4%21.4%-3.7%
GDRX_11142025_Dip_Buyer_High_CFO_Margins_ExInd_DE11142025GDRXGoodRxDip BuyDB | CFO/Rev | Low D/EDip Buy with High Cash Flow Margins
Buying dips for companies with significant cash flows from operations and reasonable debt / market cap
-7.4%-7.4%-11.8%
ASTH_11142025_Dip_Buyer_High_FCF_Yield_ExInd_DE_RevG11142025ASTHAstrana HealthDip BuyDB | FCF Yield | Low D/EDip Buy with High Free Cash Flow Yield
Buying dips for companies with significant free cash flow yield (FCF / Market Cap) and reasonable debt / market cap
18.0%18.0%-5.5%
SGRY_11142025_Dip_Buyer_High_FCF_Yield_ExInd_DE_RevG11142025SGRYSurgery PartnersDip BuyDB | FCF Yield | Low D/EDip Buy with High Free Cash Flow Yield
Buying dips for companies with significant free cash flow yield (FCF / Market Cap) and reasonable debt / market cap
3.9%3.9%-1.4%
TFX_11072025_Dip_Buyer_FCFYield11072025TFXTeleflexDip BuyDB | FCFY OPMDip Buy with High FCF Yield and High Margin
Buying dips for companies with high FCF yield and meaningfully high operating margin
12.2%12.2%-5.1%

Recent Active Movers

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Peer Comparisons for Prothena

Peers to compare with:

Financials

PRTAHPQHPEIBMCSCOAAPLMedian
NameProthena HP Hewlett .Internat.Cisco Sy.Apple  
Mkt Price9.5423.2624.49305.0978.16273.4051.32
Mkt Cap0.521.932.6284.9309.24,074.4158.8
Rev LTM1255,29534,29665,40257,696408,62556,496
Op Inc LTM-2223,6241,64411,54412,991130,2147,584
FCF LTM-1882,80062711,85412,73396,1847,327
FCF 3Y Avg-1442,9781,40011,75313,879100,5037,366
CFO LTM-1883,6972,91913,48313,744108,5658,590
CFO 3Y Avg-1433,6723,89613,49814,736111,5598,697

Growth & Margins

PRTAHPQHPEIBMCSCOAAPLMedian
NameProthena HP Hewlett .Internat.Cisco Sy.Apple  
Rev Chg LTM-91.2%3.2%13.8%4.5%8.9%6.0%5.2%
Rev Chg 3Y Avg846.2%-3.9%6.5%2.6%3.7%1.8%3.2%
Rev Chg Q149.0%4.2%14.4%9.1%7.5%9.6%9.4%
QoQ Delta Rev Chg LTM14.0%1.1%3.7%2.1%1.8%2.1%2.1%
Op Mgn LTM-1,885.7%6.6%4.8%17.7%22.5%31.9%12.1%
Op Mgn 3Y Avg-697.2%7.4%7.2%16.4%24.2%30.8%11.9%
QoQ Delta Op Mgn LTM522.2%-0.2%-1.4%0.6%0.4%0.1%0.2%
CFO/Rev LTM-1,595.5%6.7%8.5%20.6%23.8%26.6%14.6%
CFO/Rev 3Y Avg-590.9%6.8%12.7%21.4%26.1%28.4%17.1%
FCF/Rev LTM-1,597.0%5.1%1.8%18.1%22.1%23.5%11.6%
FCF/Rev 3Y Avg-592.2%5.5%4.6%18.6%24.6%25.6%12.1%

Valuation

PRTAHPQHPEIBMCSCOAAPLMedian
NameProthena HP Hewlett .Internat.Cisco Sy.Apple  
Mkt Cap0.521.932.6284.9309.24,074.4158.8
P/S43.60.41.04.45.410.04.9
P/EBIT-2.36.819.925.122.531.321.2
P/E-1.88.6572.736.029.941.033.0
P/CFO-2.75.911.221.122.537.516.2
Total Yield-54.6%14.1%2.3%5.0%5.4%2.8%3.9%
Dividend Yield0.0%2.5%2.1%2.2%2.1%0.4%2.1%
FCF Yield 3Y Avg-18.8%10.6%5.5%6.4%6.0%3.1%5.7%
D/E0.00.50.70.20.10.00.2
Net D/E-0.60.30.60.20.00.00.1

Returns

PRTAHPQHPEIBMCSCOAAPLMedian
NameProthena HP Hewlett .Internat.Cisco Sy.Apple  
1M Rtn-11.3%-3.6%12.7%-1.1%1.6%-2.0%-1.5%
3M Rtn1.4%-11.9%2.7%7.9%17.0%7.1%4.9%
6M Rtn56.9%-4.0%34.5%6.6%15.2%36.3%24.9%
12M Rtn-37.0%-27.0%16.2%40.5%34.5%7.5%11.8%
3Y Rtn-84.0%-3.7%67.3%141.3%79.6%114.1%73.5%
1M Excs Rtn-11.6%-5.6%12.9%-2.2%-0.0%-3.7%-3.0%
3M Excs Rtn-2.9%-16.2%-1.7%3.6%12.7%2.8%0.6%
6M Excs Rtn44.6%-16.3%22.3%-5.7%3.0%24.0%12.6%
12M Excs Rtn-53.8%-42.9%-0.7%25.0%19.9%-8.4%-4.6%
3Y Excs Rtn-164.9%-83.5%-11.2%59.6%-1.2%28.4%-6.2%

Financials

Segment Financials

Revenue by Segment
$ Mil2024202320222021
Discovery and development of novel therapies to treat diseases caused by protein dysregulation91 2011
Collaboration revenue 14  
Revenue from license and intellectual property 40  
Total91542011


Price Behavior

Price Behavior
Market Price$9.54 
Market Cap ($ Bil)0.5 
First Trading Date12/21/2012 
Distance from 52W High-40.5% 
   50 Days200 Days
DMA Price$10.23$8.79
DMA Trenddownup
Distance from DMA-6.7%8.5%
 3M1YR
Volatility47.4%63.5%
Downside Capture273.26129.45
Upside Capture226.5563.19
Correlation (SPY)39.7%17.2%
PRTA Betas & Captures as of 11/30/2025

 1M2M3M6M1Y3Y
Beta0.891.391.091.420.601.00
Up Beta-0.820.580.761.84-0.070.47
Down Beta1.200.631.241.221.481.52
Up Capture145%230%188%305%26%30%
Bmk +ve Days13263974142427
Stock +ve Days10213267123354
Down Capture117%169%66%37%93%108%
Bmk -ve Days7162452107323
Stock -ve Days10212955121389

[1] Upside and downside betas calculated using positive and negative benchmark daily returns respectively
Based On 1-Year Data
 Comparison of PRTA With Other Asset Classes (Last 1Y)
 PRTASector ETFEquityGoldCommoditiesReal EstateBitcoin
Annualized Return-37.3%15.1%17.8%72.1%8.6%4.4%-8.2%
Annualized Volatility63.1%17.2%19.4%19.3%15.2%17.0%35.0%
Sharpe Ratio-0.480.650.722.700.340.09-0.08
Correlation With Other Assets 21.0%17.3%-0.7%4.5%12.9%7.5%

ETFs used for asset classes: Sector ETF = XLV, Equity = SPY, Gold = GLD, Commodities = DBC, Real Estate = VNQ, and Bitcoin = BTCUSD
Smart multi-asset allocation framework can stack odds in your favor. Learn How
Based On 5-Year Data
 Comparison of PRTA With Other Asset Classes (Last 5Y)
 PRTASector ETFEquityGoldCommoditiesReal EstateBitcoin
Annualized Return-6.4%8.4%14.7%18.7%11.5%4.6%30.8%
Annualized Volatility83.2%14.5%17.1%15.5%18.7%18.9%48.6%
Sharpe Ratio0.250.400.700.970.500.160.57
Correlation With Other Assets 27.5%29.7%6.5%8.8%24.8%15.8%

ETFs used for asset classes: Sector ETF = XLV, Equity = SPY, Gold = GLD, Commodities = DBC, Real Estate = VNQ, and Bitcoin = BTCUSD
Smart multi-asset allocation framework can stack odds in your favor. Learn How
Based On 10-Year Data
 Comparison of PRTA With Other Asset Classes (Last 10Y)
 PRTASector ETFEquityGoldCommoditiesReal EstateBitcoin
Annualized Return-17.8%9.9%14.8%15.3%7.0%5.3%69.2%
Annualized Volatility76.7%16.6%18.0%14.7%17.6%20.8%55.8%
Sharpe Ratio0.100.490.710.860.320.220.90
Correlation With Other Assets 32.7%31.8%2.8%13.2%22.2%9.6%

ETFs used for asset classes: Sector ETF = XLV, Equity = SPY, Gold = GLD, Commodities = DBC, Real Estate = VNQ, and Bitcoin = BTCUSD
Smart multi-asset allocation framework can stack odds in your favor. Learn How

Short Interest

Short Interest: As Of Date12152025
Short Interest: Shares Quantity4,699,126
Short Interest: % Change Since 113020251.3%
Average Daily Volume692,839
Days-to-Cover Short Interest6.78
Basic Shares Quantity53,830,000
Short % of Basic Shares8.7%

Earnings Returns History

Expand for More
 Forward Returns
Earnings Date1D Returns5D Returns21D Returns
11/6/20254.8%1.0%2.4%
8/4/20251.3%10.5%20.9%
5/8/20254.6%-5.4%-26.1%
2/20/20252.0%-0.8%-15.0%
11/12/2024-0.7%-19.1%-20.4%
8/8/20244.4%6.0%3.7%
5/8/2024-4.5%-2.8%-8.3%
2/15/2024-1.8%-4.6%-12.0%
...
SUMMARY STATS   
# Positive111010
# Negative131414
Median Positive4.4%4.4%6.0%
Median Negative-4.4%-5.0%-16.0%
Max Positive12.0%51.0%93.8%
Max Negative-8.3%-19.1%-26.1%

SEC Filings

Expand for More
Report DateFiling DateFiling
09/30/202511/06/202510-Q (09/30/2025)
06/30/202508/04/202510-Q (06/30/2025)
03/31/202505/08/202510-Q (03/31/2025)
12/31/202402/27/202510-K (12/31/2024)
09/30/202411/12/202410-Q (09/30/2024)
06/30/202408/08/202410-Q (06/30/2024)
03/31/202405/08/202410-Q (03/31/2024)
12/31/202302/22/202410-K (12/31/2023)
09/30/202311/02/202310-Q (09/30/2023)
06/30/202308/03/202310-Q (06/30/2023)
03/31/202305/04/202310-Q (03/31/2023)
12/31/202202/28/202310-K (12/31/2022)
09/30/202211/03/202210-Q (09/30/2022)
06/30/202208/08/202210-Q (06/30/2022)
03/31/202205/05/202210-Q (03/31/2022)
12/31/202102/25/202210-K (12/31/2021)

Insider Activity

Expand for More
 OwnerTitleFiling DateActionPriceSharesTransacted
Value
Value of
Held Shares
Form
0EcoR1 Capital, LLC5062025Sell8.363,317,93827,744,92969,123,978Form