PRTA — Prothena Corporation plc stock price, charts and financials

Latest market price

8.33

+0.21+2.59%

Overview Short InterestFilings

PRTAQT42Prothena Corporation plc·NASDAQ

Overview Short InterestFilings

8.33+2.59%

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Signal & projected range

Insider selling clusterHistorical pattern — not a prediction

Recent priceDays this stock last showed the setupRange of past outcomes (±1σ)

Horizon

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Over the next 20 trading days, similar setups historically landed in a measured range of outcomes. Unlock with Premium to see the median return, the typical range, and how often they were positive. This is the historical range of outcomes — not a prediction of this stock’s price.

Ranges describe how this exact setup resolved in the past — derived from thousands of historical occurrences across QuoTrend’s coverage since 2006, survivorship-corrected to include companies that later delisted. The band is the typical spread (±1σ) of those outcomes, not a forecast; the central value is their average move. Fewer matching cases over longer horizons widen the band and lower its reliability. Backtested results are hypothetical, based on historical data, and do not represent actual trading. Past performance does not guarantee or predict future results. QuoTrend is an educational research tool, not investment advice. Markets involve risk, including loss of principal.

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IOVA+6.14%$4.32 FTRE-1.20%$18.94 SLS+12.09%$11.22 URGN+0.92%$38.59 MESO+2.12%$14.47 TSHA-1.37%$5.78 TYRA+0.50%$32.04 AUPH-2.08%$14.57

Snapshot

Index	-	P/E	-	EPS (ttm)	-5.22	Insider Own	23.00%	Shs Outstand	52.35M	Perf Week	-7.20%

Market Cap	425.11M	Forward P/E	-	EPS next Y	-1.03	Insider Trans	2.73%	Shs Float	46.19M	Perf Month	-15.24%

Enterprise Value	103.30M	PEG	0.01	EPS next Q	-	Inst Own	-	Short Float	17.75%	Perf Quarter	-26.58%

Income	-147.34M	P/S	7.34	EPS this Y	98.63%	Inst Trans	-	Short Ratio	15.16	Perf Half Y	-10.38%

Sales	57.94M	P/B	1.40	EPS next Y	-1337.20%	ROA	-43.21%	Short Interest	8.20M	Perf YTD	-14.97%

Book/sh	-	P/C	-	EPS next 5Y	-	ROE	-49.88%	52W High	12.11 -31.19%	Perf Year	18.02%

Cash/sh	-	P/FCF	-	EPS past 3/5Y	-	ROIC	-39.43%	52W Low	6.78 22.84%	Perf 3Y	-86.97%

Dividend Est.	-	EV/EBITDA	-	Sales past 3/5Y	-43.00% 58.49%	Gross Margin	46.84%	Volatility	4.63% 4.69%	Perf 5Y	-84.37%

Dividend TTM	-	EV/Sales	1.78	EPS Y/Y TTM	-129.96%	Oper. Margin	-217.94%	ATR (14)	0.43	Perf 10Y	-84.78%

Dividend Ex-Date	-	Quick Ratio	10.43	Sales Y/Y TTM	-91.85%	Profit Margin	-260.92%	RSI (14)	35.14	Recom	2.36

Dividend Gr. 3/5Y	-	Current Ratio	10.43	EPS Q/Q	153.57%	SMA20	-7.95%	Beta	-0.32	Target Price	24.50

Payout	0.00%	Debt/Eq	0.02	Sales Q/Q	1600.00%	SMA50	-10.32%	Rel Volume	0.94	Prev Close	8.12

Employees	67	LT Debt/Eq	0.04	Earnings	Aug 06	SMA200	-15.75%	Avg Volume	581.09K	Price	8.33

IPO Date	Dec 20, 2012	Option/Short	Yes / Yes	EPS/Sales Surpr.	272.25% 6215.17%	Net Debt/EBITDA	4.31	Volume	545,490	Change	2.59%

Analyst Ratings

Date	Action	Analyst	Rating	Target
Jul-24-26	Reiterated	H.C. Wainwright	Buy	$20 → $30
Mar-13-26	Reiterated	Stifel Nicolaus		$19
Dec-01-25	Reiterated	JMP Securities	Market Outperform	$11 → $19
Dec-01-25	Reiterated	Deutsche Bank	Buy	$19
Oct-28-25	Reiterated	UBS	Buy	$15
Oct-28-25	Reiterated	Piper Sandler	Overweight
Oct-07-25	Reiterated	HC Wainwright & Co.	Buy	$20
Sep-02-25	Reiterated	JMP Securities	Market Outperform	$11
May-28-25	Downgrade	B of A Securities	Neutral → Underperform
May-27-25	Downgrade	Oppenheimer	Outperform → Perform

Latest News

Jul-22-26

Jul-22-2603:42AM

Prothena (NASDAQ:PRTA) Share Price Passes Below 200-Day Moving Average – Time to Sell?defenseworld.net

Jul-21-26

Jul-21-2608:05AM

12 Health Care Stocks Moving In Tuesday's Pre-Market SessionBenzinga

Jul-09-26

Jul-09-2612:40PM

PRTA Stock Rises Nearly 11% in Six Months: What's Driving It?zacks.com

Company

Prothena Corporation plc, a late-stage clinical biotechnology company, focuses on discovery and development of novel therapies to treat diseases caused by protein dysregulation. Its product pipeline includes Prasinezumab, an investigational humanized monoclonal antibody which is in Phase 3 clinical trial for the treatment of parkinson's disease and other synucleinopathies. The company also develops Coramitug, an investigational antibody, which is in Phase 3 clinical trial for the treatment of transthyretin amyloidosis; BMS-986446, an anti-tau antibody which is in Phase 2 clinical trial to treat Alzheimer's disease; PRX019, an investigational antibody which is in Phase 1 clinical trial for the treatment of neurodegenerative diseases; and PRX123, a Dual Aß-Tau Vaccine, which is in preclinical trial for treating Alzheimer's disease. In addition, it develops discovery- and late-preclinical-stage programs include TDP-43 CYTOPE for the treatment of amyotrophic lateral sclerosis; PRX012, a next-generation anti-Aß antibody which is in phase 1 clinical trial to treat Alzheimer's disease; and PRX012-TfR, a preclinical program for the treatment of Alzheimer's disease. It 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 a-synuclein, including prasinezumab; and master collaboration agreement with Bristol Myers Squibb to develop and commercialize antibodies targeting tau, TDP-43. Prothena Corporation plc was incorporated in 2012 and is based in Dublin, Ireland.

Ownership

Per-holder 13F data hasn't been ingested for this ticker yet.

Financial Statements

DataTimeframe

Line Item (USD, M)	TTM —	FY 2025 12/31/2025	FY 2024 12/31/2024	FY 2023 12/31/2023	FY 2022 12/31/2022	FY 2021 12/31/2021	FY 2020 12/31/2020	FY 2019 12/31/2019	FY 2018 12/31/2018
Total Revenue	11	10	135	91	54	201	1	1	1
Cost of Goods Sold Incl. D&A	29	4	0	0	0	0	75	51	101
Gross Profit	-18	6	135	91	54	201	-74	-50	-100
Selling, General and Administrative Excl. Other	64	59	67	62	50	46	39	36	42
Research and Development	171	135	223	221	136	82	75	51	101
Other Operating Expense	3	-3	0	-1	-1	1	-75	-51	1
Operating Income	-256	-185	-155	-191	-132	72	-113	-86	-159
Interest Expense	0	0	0	0	0	0	0	0	4
Unusual Expense	—	—	—	—	—	—	—	—	—
Non-Operating Income (Expense)	17	-16	26	31	6	0	2	8	6
Net Income Before Taxes	-238	-201	-129	-160	-126	72	-111	-77	-156
Income Taxes	42	43	-7	-13	-9	5	0	0	0
Consolidated Net Income	-281	-244	-122	-147	-117	67	-111	-78	-156
Net Income From Continuing Operations	-281	-244	-122	-147	-117	67	-111	-78	-156
Net Income	-281	-244	-122	-147	-117	67	-111	-78	-156
EPS (Recurring)	-5.22	-4.53	-2.27	-2.76	-2.47	1.51	-2.78	-1.95	-3.93
EPS (Basic, Before Extraordinaries)	-5.22	-4.53	-2.27	-2.76	-2.47	1.51	-2.78	-1.95	-3.93
EPS (Diluted)	-5.22	-4.53	-2.27	-2.76	-2.47	1.38	-2.78	-1.95	-3.93
EBITDA	-208	-197	-128	-160	-125	73	-111	-84	-153
Other After Tax Adjustments	—	—	—	—	—	—	—	—	—
Stock Option Compensation Expense	—	—	—	—	—	—	—	—	—
Price To Earnings Ratio	—	—	—	—	—	35.80	—	—	—
Price To Sales Ratio	40.89	51.57	5.54	21.17	52.44	10.81	480.40	633.20	412.00
Gross Margin	-163.64	60.00	100.00	100.00	100.00	100.00	-7,400.00	-5,000.00	-10,000.00
Operating Margin	-2,327.27	-1,850.00	-114.81	-209.89	-244.44	35.82	-11,300.00	-8,600.00	-15,900.00
Net Margin	-2,554.55	-2,440.00	-90.37	-161.54	-216.67	33.33	-11,100.00	-7,800.00	-15,600.00
Shares Outstanding	54	54	54	53	47	44	40	40	40
Market Capitalization	450	516	748	1,926	2,832	2,174	480	633	412
Operating Lease Expense	—	—	—	—	—	—	—	—	—

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Insider Trading Volume

Insider Trading

Insider	Relationship	Date	Transaction	Cost	#Shares	Value ($)	#Shares Total	SEC Form 4
Kingston Anne Evans	Chief Strategy Officer	Jul 29 '26	Sale	8.47	7,662	64,919	55,782	Jul 30
Isaacs Michael John	General Counsel & Company Sec.	Jul 29 '26	Sale	8.47	8,386	71,055	35,745	Jul 30
Swanson Chad J.	Chief Development Officer	Jul 28 '26	Option Exercise	0.00	51,000	0	85,000	Jul 30
Zago Wagner M.	Chief Scientific Officer	Jul 28 '26	Option Exercise	0.00	51,000	0	85,000	Jul 30
Smith Brandon S.	Chief Operating Officer	Jul 28 '26	Option Exercise	0.00	78,000	0	130,000	Jul 30
Nguyen Tran	Chief Strategy Officer and CFO	Jul 28 '26	Option Exercise	0.00	57,000	0	97,205	Jul 30
Kinney Gene G.	President and CEO	Jul 28 '26	Option Exercise	0.00	84,000	0	152,793	Jul 30
Walker Karin L	Chief Accounting Officer	Jul 28 '26	Option Exercise	0.00	15,000	0	25,000	Jul 30
SCULLY WILLIAM P	10% Owner	Jun 16 '26	Buy	7.90	20,000	157,990	756,000	Jun 18
SCULLY WILLIAM P	10% Owner	Jun 11 '26	Buy	8.17	125,000	1,021,225	1,061,000	Jun 12
SCULLY WILLIAM P	10% Owner	Jun 04 '26	Buy	9.31	50,000	465,295	936,000	Jun 05
SCULLY WILLIAM P	10% Owner	Jun 02 '26	Buy	9.43	50,000	471,300	886,000	Jun 03
SCULLY WILLIAM P	10% Owner	May 22 '26	Buy	9.81	100,000	981,300	836,000	May 26
EcoR1 Capital, LLC	10% Owner	May 06 '25	Sale	7.64	1,984,053	15,164,712	5,304,596	May 06
EcoR1 Capital, LLC	10% Owner	May 05 '25	Sale	8.11	977,693	7,930,166	7,288,649	May 06

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