Prothena Corp. Plc (PRTA)

Prothena reported its third-quarter 2025 financial results with an EPS of $-0.68, which was $0.04 better than the analyst estimate. H.C. Wainwright raised its price target on Prothena to $30.00 from $20.00 on November 10, 2025. Citizens raised its price target to $19.00 from $11.00 on December 1, 2025. Deutsche Bank Aktiengesellschaft set a $19.00 target price on Prothena on December 1, 2025. Citigroup reissued a "market outperform" rating on December 1, 2025. Chardan Capital raised Prothena to a "strong-buy" rating on November 19, 2025. Wall Street Zen raised shares from a "sell" to a "hold" rating on November 8, 2025. Weiss Ratings restated a "sell (e+)" rating on December 29, 2025. Prothena presented preclinical data on its TDP-43 CYTOPE program at the Neuroscience 2025 conference on November 19, 2025. Phase 2 clinical trial data for coramitug was published in Circulation on November 11, 2025. Novo Nordisk announced it would advance coramitug into Phase 3 development for ATTR amyloidosis with cardiomyopathy in 2025. Paula Cobb stepped down from Prothena's board of directors on December 12, 2025, to join Manifold Bio. Over the past six months, the stock has seen a +15.41% change, with a 52-week range between $4.32 and $16.67.

Demand seasonality is not directly applicable to Prothena's products and services, as its revenue is primarily derived from license fees and collaboration agreements. Historically, implied volatility for PRTA tends to rise most in April and decline to its lowest levels in September.

Prothena Corporation Plc is a clinical-stage biotechnology company based in Dublin, Ireland, specializing in novel therapies for diseases caused by protein dysregulation, focusing on neurodegenerative, rare, and peripheral amyloid diseases. Its pipeline includes Prasinezumab for Parkinson's disease, Coramitug for transthyretin amyloidosis, BMS-986446 for Alzheimer's disease, PRX012 for Alzheimer's disease, PRX123 a Dual Aβ-Tau Vaccine for treating Alzheimer's disease, PRX019 for neurodegenerative diseases, and Birtamimab for AL amyloidosis.

Prothena Corporation Plc is headquartered in Dublin, Ireland, with a primary focus in the United States for the discovery and development of novel therapies. The company maintains a presence in the US and several other countries worldwide within the global health sector.

Prothena's brand reputation is influenced by its clinical pipeline advancements and analyst sentiment. As of February 2026, Prothena has received a consensus recommendation of "Hold" from twelve analysts, with two sell, four hold, five buy, and one strong buy recommendation. Positive news regarding its pipeline, such as Novo Nordisk advancing coramitug into Phase 3 development and presentations at neuroscience conferences, contributes positively to its scientific and development reputation.

Institutional investors hold 97.08% of Prothena's stock. Major institutional owners include Fmr Llc, BlackRock, Inc., Vanguard Group Inc., Armistice Capital, Llc, Rubric Capital Management LP, ADAR1 Capital Management, LLC, Palo Alto Investors LP, D. E. Shaw & Co., Inc., Acadian Asset Management Llc, and Geode Capital Management, Llc. William P Scully and Todd W Fennell are significant individual shareholders.