Prothena Corporation plc Ordinary Shares (PRTA) Stock Price

PRTAStock

$9.33+13.23%52W

Market Cap$478.97M

P/E—

PEG Ratio—

Div yield—

Beta-0.33

PRTA Share Price Chart

Favorite Metrics

Price vs S&P 500 (26W)-7.92%

Price vs S&P 500 (4W)10.46%

VGM Score60.02

Book Value / Share (Quarterly)$5.54

P/TBV (Annual)1.02x

Indicated Dividend (Annual)$0.00

Revenue Growth (3Y)-43.57%

Cash Flow / Share (Quarterly)$-1.17

Price vs S&P 500 (YTD)-15.12%

Net Profit Margin (TTM)-80.67%

EPS (TTM)$-0.83

10-Day Avg Trading Volume0.35M

EPS Excl Extra (TTM)$-0.83

Revenue Growth (5Y)60.83%

EPS (Annual)$-4.53

ROI (Annual)-87.03%

Net Profit Margin (5Y Avg)-591.09%

Cash / Share (Quarterly)$5.57

Revenue Growth QoQ (YoY)-77.15%

ROA (Last FY)-74.69%

Revenue Growth TTM (YoY)427.32%

EBITD / Share (TTM)$-1.02

ROE (5Y Avg)-28.55%

Operating Margin (TTM)-101.80%

Cash Flow / Share (Annual)$-3.04

P/B Ratio1.62x

P/B Ratio (Quarterly)1.79x

Net Income / Employee (Annual)$-3,643,200

EV / Revenue (TTM)3.26x

Net Interest Coverage (TTM)-1575.00x

ROA (TTM)-13.21%

EV / EBITDA (TTM)2.65x

EPS Incl Extra (Annual)$-4.53

Current Ratio (Annual)7.72x

Quick Ratio (Quarterly)24.82x

3-Month Avg Trading Volume0.52M

52-Week Price Return13.23%

Revenue / Employee (TTM)$813,900

Tangible BV / Share (Quarterly)$6.66

P/S Ratio (Annual)48.13x

Asset Turnover (Annual)0.03x

52-Week High$11.80

Operating Margin (5Y Avg)-549.63%

EPS Excl Extra (Annual)$-4.53

CapEx CAGR (5Y)-7.15%

Tangible BV CAGR (5Y)8.84%

26-Week Price Return4.01%

Quick Ratio (Annual)7.57x

13-Week Price Return-6.51%

Total Debt / Equity (Annual)0.00x

Current Ratio (Quarterly)25.05x

Enterprise Value$177.95M

Revenue / Share Growth (5Y)51.42%

Asset Turnover (TTM)0.16x

Book Value / Share Growth (5Y)2.47%

Revenue / Employee (Annual)$144,500

Pretax Margin (Annual)-2073.82%

Cash / Share (Annual)$5.71

3-Month Return Std Dev46.82%

Net Income / Employee (TTM)$-656,600

ROE (Last FY)-87.03%

EPS Basic Excl Extra (Annual)$-4.53

P/FCF (TTM)16.14x

Receivables Turnover (TTM)52.40x

Total Debt / Equity (Quarterly)0.00x

EPS Incl Extra (TTM)$-0.83

Receivables Turnover (Annual)52.40x

ROI (TTM)-14.98%

P/S Ratio (TTM)8.55x

Pretax Margin (5Y Avg)-508.41%

Revenue / Share (Annual)$0.18

Tangible BV / Share (Annual)$7.15

Forward P/E85.41x

Price vs S&P 500 (52W)-5.33%

Year-to-Date Return-2.30%

5-Day Price Return-0.64%

EPS Normalized (Annual)$-4.53

ROA (5Y Avg)-24.52%

Net Profit Margin (Annual)-2520.57%

Month-to-Date Return14.90%

Cash Flow / Share (TTM)$-1.36

EBITD / Share (Annual)$-3.97

Operating Margin (Annual)-2216.44%

ROI (5Y Avg)-28.55%

EPS Basic Excl Extra (TTM)$-0.83

P/TBV (Quarterly)1.01x

P/B Ratio (Annual)1.83x

Pretax Margin (TTM)-81.33%

Book Value / Share (Annual)$5.21

Price vs S&P 500 (13W)-8.47%

Beta-0.33x

P/FCF (Annual)5.07x

Revenue / Share (TTM)$1.05

ROE (TTM)-14.98%

52-Week Low$7.73

vGradeB

gGradeB

mGradeC

vgmGradeB

PRTA Earnings Surprise History

Quarter	Report date	EPS estimate	EPS actual	Surprise
Q2 2026	Aug 6, 2026	-$0.38	-$0.31	+18.39%(+$0.07)
Q1 2026	May 7, 2026	-$0.30	$0.68	+324.00%(+$0.99)
Q4 2025	Feb 19, 2026	-$0.46	-$0.46	+0.67%(+$0.00)
Q3 2025	Nov 6, 2025	-$0.54	-$0.67	-24.65%(-$0.13)
Q2 2025	Aug 4, 2025	-$1.79	-$1.73	+3.31%(+$0.06)

PRTA Analyst Recommendations

May 2026

Jun 2026

Jul 2026

Aug 2026

3.75

Industry Peers — Pharmaceuticals(570)

Symbol	Value Score	Growth Score	Momentum Score	Price
PRTAProthena Corporation plc Ordinary Shares	B	B	C	$9.33
LLYEli Lilly & Co.	D	B	C	$1174.61
JNJJohnson & Johnson	D	C	B	$268.04
ABBVABBVIE INC.	D	C	B	$255.48
MRKMerck & Co., Inc.	D	C	B	$148.35
NVSNovartis AG	C	C	C	$153.81
AZNAstraZeneca PLC	C	B	C	$162.70
NVONovo-Nordisk A/S	B	C	C	$45.61
ABTAbbott Laboratories	C	C	C	$112.47
PFEPfizer Inc.	C	D	B	$27.96
VRTXVertex Pharmaceuticals Inc	D	C	B	$541.69
BMYBristol-Myers Squibb Co.	B	B	B	$66.58
SNYSanofi American Depositary Shares (Each representing one-half of one ordinary share)	B	C	C	$44.82
GSKGSK plc American Depositary Shares (Each representing two Ordinary Shares)	B	C	C	$50.82
REGNRegeneron Pharmaceuticals Inc	C	C	B	$794.19
TAKTakeda Pharmaceutical Company Limited American Depositary Shares (each representing 1/2 of a share of Common Stock)	C	C	B	$18.03
TEVATeva Pharmaceutical Industries Limited American Depositary Shares	C	C	C	$36.44
ONCBeOne Medicines Ltd. American Depositary Shares	D	B	B	$366.73
RPRXRoyalty Pharma plc Class A Ordinary Shares	D	D	B	$60.85
ZTSZOETIS INC.	C	C	D	$77.34
ALNYAlnylam Pharmaceuticals, Inc.	D	A	D	$237.10
INSMInsmed, Inc.	F	A	C	$118.54
ROIVRoivant Sciences Ltd. Common Shares	D	F	B	$34.71
UTHRUnited Therapeutics Corp	C	C	B	$515.46
GMABGenmab A/S ADS	C	C	B	$33.23
VTRSViatris Inc. Common Stock	B	C	B	$16.34
ASNDAscendis Pharma A/S Ordinary Share	D	A	C	$247.91
JAZZJazz Pharmaceuticals, Inc.	B	C	B	$244.54
BBIOBridgeBio Pharma, Inc. Common Stock	F	A	B	$76.60
BMRNBioMarin Pharmaceuticals Inc	C	C	B	$64.67
MDGLMadrigal Pharmaceuticals, Inc. Common Stock	D	A	B	$533.76
CORTCorcept Therapeutics Inc.	F	C	B	$113.88
ELANElanco Animal Health Incorporated Common Stock	C	B	C	$24.11
ARWRArrowhead Research Corporation	D	A	B	$84.91
SMMTSummit Therapeutics Inc. Common Stock	F	—	D	$13.73
AXSMAxsome Therapeutics, Inc	D	B	C	$199.02
RDYDr. Reddy's Laboratories Limited American Depositary Shares	D	D	C	$12.18
IONSIonis Pharmaceuticals, Inc. Common Stock	D	D	C	$61.05
CYTKCytokinetics Inc.	F	D	C	$72.09
ABVXAbivax SA American Depositary Shares	—	—	C	$113.35
NUVLNuvalent, Inc. Class A Common Stock	—	—	B	$123.96
PRAXPraxis Precision Medicines, Inc. Common Stock	F	—	B	$344.75
PTGXProtagonist Therapeutics, Inc	F	B	B	$144.33
CRNXCrinetics Pharmaceuticals, Inc.	F	A	A	$84.84
TGTXTG Therapeutics, Inc.	D	B	B	$53.93
SYRESpyre Therapeutics, Inc. Common Stock	—	—	B	$90.36
ALKSAlkermes Inc. plc	D	C	B	$47.41
RYTMRhythm Pharmaceuticals, Inc. Common Stock	F	B	C	$107.17
ERASErasca, Inc. Common Stock	—	—	A	$18.03
TVTXTravere Therapeutics, Inc. Common Stock	F	B	A	$65.67
BLTEBelite Bio, Inc American Depositary Shares	—	—	C	$151.72

About Prothena Corporation plc Ordinary Shares

Prothena is a late-stage clinical biotechnology company developing treatments for neurodegenerative and amyloid diseases using its proprietary CYTOPE platform, which targets intracellular disease pathways in the brain and body. The company's pipeline includes Prasinezumab for Parkinson's disease, Coramitug for ATTR amyloidosis, and partnered programs targeting Alzheimer's disease and ALS. Prothena combines wholly-owned and partnered assets to address protein-dysregulation disorders with significant unmet medical needs.

PRTA Next Earnings Report

Report dateNov 5, 2026

QuarterQ3 2026

Report timeAMC

EPS estimate-$0.38

Revenue estimate$9.58M

Scheduled date with consensus estimates — both can change before the company reports.

Earnings calendar for November 2026

PRTA Insider Transactions

BuyAug 20, 2026
SCULLY WILLIAM P
Beneficial Owner of more than 10% of a Class of Security
Shares: 50,000Value: $439,430
BuyAug 7, 2026
SCULLY WILLIAM P
Beneficial Owner of more than 10% of a Class of Security
Shares: 37,500Value: $323,220
SellJul 29, 2026
ISAACS MICHAEL JOHN
General Counsel
Shares: 8,386Value: $71,055
SellJul 29, 2026
KINGSTON ANNE EVANS
Officer
Shares: 7,662Value: $64,919
BuyJun 16, 2026
SCULLY WILLIAM P
Beneficial Owner of more than 10% of a Class of Security
Shares: 20,000Value: $157,990

Open-market buys and sells filed with the SEC over the last 90 days. Grants, gifts and option exercises are excluded.

All insider transactions for August 2026

Analyst Sentiment

3.8

Buy

Consensus rating

52-Week Range

Low$7.73

High$11.80