Tearsheet

Prothena (PRTA)

Market Price (11/5/2025): $10.265 | Market Cap: $552.5 Mil
Sector: Health Care | Industry: Biotechnology

Prothena (PRTA)

Market Price (11/5/2025): $10.265
Market Cap: $552.5 Mil
Sector: Health Care
Industry: Biotechnology

Investment Highlights Why It Matters Which of these 2 stories sounds closer for this stock?

1. Generates cash flow

The stock generated 4% or more of the share price (called cash flow yield), and shows moderate 10-15% or more growth.

2. Riding a trend

Think Tesla during the pandemic of 2020 when EVs were riding a cultural high, or Nvidia in the current AI boom, or even Figma. These companies don’t have enough yield, or, enough growth, or both - however - they are riding a trend. They have momentum. These can be more volatile - they don’t have the floor of strong cash flow

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 -65%	Weak multi-year price returns 2Y Excs Rtn is -133%, 3Y Excs Rtn is -157%	Not profitable at operating income level Op Inc LTMOperating Income, Last Twelve Months is -249 Mil, Op Mgn LTMOperating Margin = Operating Income / Revenue Reflects profitability before taxes and before impact of capital structure (interest payments). is -2408%
1			Weak revenue growth Rev Chg LTMRevenue Change % Last Twelve Months (LTM) is -95%, Rev Chg QQuarterly Revenue Change % is -97%
2			Not cash flow generative CFO/Rev LTMCash Flow from Operations / Revenue (Sales), Last Twelve Months (LTM) is -1863%, FCF/Rev LTMFree Cash Flow / Revenue (Sales), Last Twelve Months (LTM) is -1865%
3			Valuation getting more expensive P/S 6M Chg %Price/Sales change over 6 months. Declining P/S indicates valuation has become less expensive. is 473%
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%

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 -65%
1	Weak multi-year price returns 2Y Excs Rtn is -133%, 3Y Excs Rtn is -157%
2	Not profitable at operating income level Op Inc LTMOperating Income, Last Twelve Months is -249 Mil, Op Mgn LTMOperating Margin = Operating Income / Revenue Reflects profitability before taxes and before impact of capital structure (interest payments). is -2408%
3	Weak revenue growth Rev Chg LTMRevenue Change % Last Twelve Months (LTM) is -95%, Rev Chg QQuarterly Revenue Change % is -97%
4	Not cash flow generative CFO/Rev LTMCash Flow from Operations / Revenue (Sales), Last Twelve Months (LTM) is -1863%, FCF/Rev LTMFree Cash Flow / Revenue (Sales), Last Twelve Months (LTM) is -1865%
5	Valuation getting more expensive P/S 6M Chg %Price/Sales change over 6 months. Declining P/S indicates valuation has become less expensive. is 473%
6	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%

Market Valuation & Key Metrics

	11/5/25	2024	2023	2022	2021
Share Price CYE	$10.27	$13.85	$36.34	$60.25	$49.40
Market Cap CYE ($ Mil)	552.5	745.4	1,950.4	2,950.9	2,304.3
Total Debt ($ Mil)	9.8	10.8	11.8	6.5	12.3
Total Cash ($ Mil)	371.4	471.4	618.8	710.4	579.1
Enterprise Value ($ Mil)	190.9	756.2	1,962.2	2,957.4	2,316.6
Valuation Ratios
P/S TTM	53.4	5.5	21.2	52.9	10.9
P/EBIT TTM	-2.2	-4.8	-10.1	-21.7	30.4
P/E TTM	-1.8	-6.1	-13.2	-24.4	32.6
Sector Ratios
P/S TTM (Sector)	4.0	3.5	4.0	4.6	7.3
P/EBIT TTM (Sector)	-1.6	-1.3	-1.3	-1.3	-2.7
P/E TTM (Sector)	-1.9	-1.5	-1.5	-1.3	-2.8

	11/5/25	2024	2023
Share Price CYE	$10.27	$13.85	$36.34
Market Cap CYE ($ Mil)	552.5	745.4	1,950.4
Total Debt ($ Mil)	9.8	10.8	11.8
Total Cash ($ Mil)	371.4	471.4	618.8
Enterprise Value ($ Mil)	190.9	756.2	1,962.2
Valuation Ratios
P/S TTM	53.4	5.5	21.2
P/EBIT TTM	-2.2	-4.8	-10.1
P/E TTM	-1.8	-6.1	-13.2
Sector Ratios
P/S TTM (Sector)	4.0	3.5	4.0
P/EBIT TTM (Sector)	-1.6	-1.3	-1.3
P/E TTM (Sector)	-1.9	-1.5	-1.5

	PRTA	S&P 500
REVENUE GROWTH	POOR
Rev LTM ($ Bil)	0.0
Rev Chg Q	-96.7%	6.7%
Rev Chg LTM	-95.2%	5.6%
Rev Chg 3Y Avg	40.7%	5.3%
PROFITABILITY	VERY POOR
Op Inc LTM ($ Bil)	-0.2
CFO LTM ($ Bil)	-0.2
Net Inc LTM ($ Bil)	-0.3
Op Mgn LTM	-2,407.9%	18.8%
CFO/Rev LTM	-1,863.1%	20.4%
Net Inc Mgn	-2,929.3%	12.9%
VALUATION	VERY HIGH
P/S	53.4	3.1
P/CFO	-2.9	15.2
P/FCF	-2.9	20.3
P/E	-1.8	23.7
STABILITY	VERY GOOD
Debt/Equity	0.02	0.21
Cash/Assets	0.93	0.07

AI Generated Analysis | Feedback

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PRTA Stock

Return (1M):

Factor Drivers of Stock Movement

The 45.9% change in PRTA stock from 8/5/2025 to 11/4/2025 was primarily driven by a 45.9% change in the company's P/S Multiple.

	8052025	11042025	Change
Stock Price ($)	7.03	10.26	45.95%
Change Contribution By	LTM	LTM
Total Revenues ($ Mil)	10.34	10.34	0.00%
P/S Multiple	36.59	53.41	45.95%
Shares Outstanding (Mil)	53.83	53.83	0.00%
Cumulative Contribution			45.95%

LTM = Last Twelve Months as of date shown

The 39.6% change in PRTA stock from 5/6/2025 to 11/4/2025 was primarily driven by a 1724.8% change in the company's P/S Multiple.

	5062025	11042025	Change
Stock Price ($)	7.35	10.26	39.59%
Change Contribution By	LTM	LTM
Total Revenues ($ Mil)	135.16	10.34	-92.35%
P/S Multiple	2.93	53.41	1724.81%
Shares Outstanding (Mil)	53.82	53.83	-0.02%
Cumulative Contribution			39.59%

LTM = Last Twelve Months as of date shown

The -37.7% change in PRTA stock from 11/4/2024 to 11/4/2025 was primarily driven by a -95.2% change in the company's Total Revenues ($ Mil).

	11042024	11042025	Change
Stock Price ($)	16.46	10.26	-37.67%
Change Contribution By	LTM	LTM
Total Revenues ($ Mil)	217.25	10.34	-95.24%
P/S Multiple	4.07	53.41	1210.97%
Shares Outstanding (Mil)	53.77	53.83	-0.11%
Cumulative Contribution			-37.67%

LTM = Last Twelve Months as of date shown

The -81.2% change in PRTA stock from 11/5/2022 to 11/4/2025 was primarily driven by a -89.3% change in the company's P/S Multiple.

	11052022	11042025	Change
Stock Price ($)	54.56	10.26	-81.20%
Change Contribution By	LTM	LTM
Total Revenues ($ Mil)	5.15	10.34	100.64%
P/S Multiple	497.39	53.41	-89.26%
Shares Outstanding (Mil)	46.99	53.83	-14.56%
Cumulative Contribution			-81.59%

LTM = Last Twelve Months as of date shown

Why The Stock Moved

AI Generated Analysis | Feedback

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Return vs. Risk

Price Returns Compared

	2020	2021	2022	2023	2024	2025	Total [1]
Returns
PRTA Return	-24%	311%	22%	-40%	-62%	-26%	-32%
Peers Return	-15%	-9%	-6%	-3%	-3%	-17%	-44%
S&P 500 Return	16%	27%	-19%	24%	23%	15%	112%
Monthly Win Rates [3]
PRTA Win Rate	58%	58%	50%	42%	25%	70%
Peers Win Rate	18%	15%	23%	31%	22%	62%
S&P 500 Win Rate	58%	75%	42%	67%	75%	70%
Max Drawdowns [4]
PRTA Max Drawdown	-52%	-8%	-54%	-46%	-67%	-67%
Peers Max Drawdown	-20%	-13%	-14%	-15%	-30%	-27%
S&P 500 Max Drawdown	-31%	-1%	-25%	-1%	-2%	-15%

[1] Cumulative total returns since the beginning of 2020
[2] Peers: VRTX, APM, BBOT, GDTC, HIND. 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 11/4/2025 (YTD)

How Low Can It Go

Unique Key	Event	PRTA	S&P 500
2022 Inflation Shock	2022 Inflation Shock
2022 Inflation Shock% Loss	% Loss	-71.2%	-25.4%
2022 Inflation Shock% Gain to Breakeven	% Gain to Breakeven	247.1%	34.1%
2022 Inflation ShockTime to Breakeven	Time to Breakeven	Not Fully Recovered days	464 days
2020 Covid Pandemic	2020 Covid Pandemic
2020 Covid Pandemic% Loss	% Loss	-52.4%	-33.9%
2020 Covid Pandemic% Gain to Breakeven	% Gain to Breakeven	109.9%	51.3%
2020 Covid PandemicTime to Breakeven	Time to Breakeven	331 days	148 days
2018 Correction	2018 Correction
2018 Correction% Loss	% Loss	-89.8%	-19.8%
2018 Correction% Gain to Breakeven	% Gain to Breakeven	883.3%	24.7%
2018 CorrectionTime to Breakeven	Time to Breakeven	735 days	120 days

Compare to VRTX, APM, BBOT, GDTC, HIND

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.

Preserve Wealth

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Asset Allocation

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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 Generated Analysis | Feedback

Here are 1-3 brief analogies for Prothena (PRTA):

Prothena is like **Biogen**, but with a more specialized focus on developing protein immunotherapies for a range of neurodegenerative diseases, including Parkinson's and ATTR amyloidosis.
Think of Prothena as a specialized **Vertex Pharmaceuticals**, but instead of tackling cystic fibrosis, they're focused on pioneering treatments for neurodegenerative diseases driven by protein misfolding and aggregation.

AI Generated Analysis | Feedback

Prasinezumab (PRX002): An investigational antibody designed to target alpha-synuclein for the potential treatment of Parkinson's disease.
Birtamimab (NEOD001): An investigational antibody designed to target amyloid fibrils for the potential treatment of AL amyloidosis.
PRX012: An investigational antibody targeting amyloid-beta (Aβ) for the potential treatment of Alzheimer's disease.
Tau Program (PRX005): An investigational program targeting tau protein for the potential treatment of Alzheimer's disease.
ATTR Amyloidosis Program: An investigational program targeting transthyretin (ATTR) for the potential treatment of ATTR amyloidosis.

AI Generated Analysis | Feedback

Prothena (PRTA) is a clinical-stage biotechnology company. Its business model primarily involves the development of therapeutic antibodies for diseases of protein misfolding. As such, Prothena does not sell products directly to individuals. Instead, it generates revenue primarily through strategic collaborations and licensing agreements with larger pharmaceutical companies that license Prothena's drug candidates or platforms, providing upfront payments, research funding, and potential milestone payments.

Therefore, Prothena's major "customers" are other companies. The significant customer companies/partners for Prothena include:

Bristol Myers Squibb (Symbol: BMY)
Novo Nordisk (Symbol: NVO)

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Lonza Group AG (LONN)

AI Generated Analysis | Feedback

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AI Generated Analysis | Feedback

The emergence of gene-editing and advanced gene-silencing therapies for ATTR amyloidosis presents a clear emerging threat to Prothena’s vounemab (PRX004) program. Companies such as Intellia Therapeutics (with NTLA-2001) are developing in vivo CRISPR gene-editing treatments that aim to achieve a one-time, potentially curative-like effect by permanently reducing TTR protein production. Similarly, other companies are developing highly potent gene-silencing therapies with infrequent dosing schedules (e.g., quarterly or less). If these next-generation therapies prove safe and highly effective in late-stage clinical trials, their potential for infrequent or single-dose administration could fundamentally disrupt the treatment landscape for ATTR amyloidosis, making chronic antibody-based therapies like vounemab significantly less competitive or even obsolete for a substantial portion of the patient population.

AI Generated Analysis | Feedback

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AI Generated Analysis | Feedback

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AI Generated Analysis | Feedback

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Better Bets than Prothena (PRTA)

	PRTA	Better Performance than PRTA
Metric	Value	Industry (Biotechnology)
Rev Chg LTM	-95.2%	ABBV (6.1%), AMGN (12.9%), GILD (3.8%), VRTX (10.5%), REGN (2.9%)
Rev Chg 3Y Avg	40.7%	ALNY (51.4%), BBIO (727.6%), CYTK (824.6%), RYTM (137.5%), AXSM (699.5%)
Op Mgn LTM	-2407.9%	ABBV (23.5%), AMGN (23.5%), GILD (37.4%), VRTX (-1.7%), REGN (26.7%)
CFO/Rev LTM	-1863.1%	ABBV (33.1%), AMGN (34.4%), GILD (34.2%), VRTX (33.7%), REGN (35.6%)
FCF/Rev LTM	-1864.8%	ABBV (31.3%), AMGN (30.4%), GILD (32.5%), VRTX (30.6%), REGN (27.2%)
Total Yield	-54.9%	ABBV (4.0%), AMGN (7.3%), GILD (6.7%), VRTX (3.4%), REGN (7.5%)

	PRTA	Better Performance than PRTA
Metric	Value	Sector (Health Care)
Rev Chg LTM	-95.2%	LLY (36.8%), JNJ (5.1%), ABBV (6.1%), UNH (10.5%), ABT (6.4%)
Rev Chg 3Y Avg	40.7%	ALNY (51.4%), BBIO (727.6%), HIMS (71.0%), GMED (44.7%), CYTK (824.6%)
Op Mgn LTM	-2407.9%	LLY (43.0%), JNJ (26.2%), ABBV (23.5%), UNH (6.1%), ABT (17.6%)
CFO/Rev LTM	-1863.1%	LLY (20.5%), JNJ (26.3%), ABBV (33.1%), UNH (4.8%), ABT (20.8%)
FCF/Rev LTM	-1864.8%	LLY (-0.1%), JNJ (20.3%), ABBV (31.3%), UNH (4.0%), ABT (15.8%)
Total Yield	-54.9%	LLY (2.3%), JNJ (8.3%), ABBV (4.0%), UNH (8.5%), ABT (8.2%)

	PRTA	Better Performance than PRTA
Metric	Value	All Other Sectors
Rev Chg LTM	-95.2%	NVDA (71.6%), AAPL (6.0%), MSFT (15.6%), GOOGL (13.4%), AMZN (10.9%)
Rev Chg 3Y Avg	40.7%	NVDA (92.0%), APO (129.8%), NU (70.1%), LVS (51.6%), RDDT (45.3%)
Op Mgn LTM	-2407.9%	NVDA (58.1%), AAPL (31.9%), MSFT (46.3%), GOOGL (32.2%), AMZN (11.4%)
CFO/Rev LTM	-1863.1%	NVDA (46.6%), AAPL (26.6%), MSFT (50.0%), GOOGL (39.3%), AMZN (18.1%)
FCF/Rev LTM	-1864.8%	NVDA (43.6%), AAPL (23.5%), MSFT (26.6%), GOOGL (19.1%), AMZN (2.0%)
Total Yield	-54.9%	NVDA (1.8%), AAPL (2.8%), MSFT (3.4%), GOOGL (4.0%), AMZN (2.7%)

		Best Bets In Health Care Sector
	PRTA	RPRX	HALO	CPRX	BMY	LNTH	MEDP	PBH	MRK	NBIX	ISRG
What You Pay
P/E	-1.8	15.7	13.4	12.5	15.4	14.6	38.6	14.1	12.8	33.3	69.9
P/EBIT	-2.2	8.3	10.4	10.7	9.3	10.0	33.0	9.0	10.3	24.4	68.2
What You Get
Rev Chg Q	-96.7%	7.7%	22.1%	19.4%	2.8%	-4.1%	23.7%	-6.6%	-1.9%	27.8%	22.9%
Rev Chg LTM	-95.2%	3.0%	31.2%	28.5%	1.3%	5.7%	13.9%	0.6%	1.8%	19.6%	22.2%
Rev Chg 3Y Avg	40.7%	0.8%	29.0%	49.9%	1.0%	34.3%	19.9%	0.8%	3.7%	24.6%	16.3%
FCF/Rev 3Y Avg	-712.1%	113.4%	45.0%	38.9%	29.0%	26.1%	25.3%	21.6%	20.9%	21.1%	16.5%

[1] Choosing top 10 best bets from each sector quarterly is an alpha producing strategy vs sector benchmark
[2] Historical annualized return of 11%, alpha of 1.9%, and sharpe of 0.52

Latest Trefis Analyses

	Title	Topic	Date
0	DASHBOARDS
1	Prothena Stock Jumped 9.5% in a Week, What Now?	Return
2	Day 5 of Gains Streak for Prothena Stock with 19% Return (vs. 13% YTD) [1/27/2025]	Notification
3	Day 0 of Loss Streak for Prothena Stock with 0% Return (vs. 13% YTD) [1/26/2025]	Notification
4	Day 5 of Gains Streak for Prothena Stock with 19% Return (vs. 13% YTD) [1/25/2025]	Notification
5	Day 0 of Loss Streak for Prothena Corp Stock with 0% Return (vs. -55% YTD) [12/2/2024]	Notification
6	Day 0 of Loss Streak for Prothena Corp Stock with 0% Return (vs. -56% YTD) [11/30/2024]	Notification
7	Prothena vs. S&P500 Correlation	Correlation
8	Prothena Price Volatility	Volatility
9	Day 5 of Loss Streak for Prothena Corporation Stock with -26% Return (vs. -31% YTD) [2/6/2024]	Notification
10	Day 1 of Gains Streak for Prothena Corporation Stock with 0.04% Return (vs. -44% YTD) [10/27/2023]	Notification
11	ARTICLES
12	Will Prothena Stock Rebound After A 13% Drop Last Week?		June 23rd, 2021
13	What’s Next For Prothena Stock After A 9% Rise This Week?		April 16th, 2021

	Title
0	DASHBOARDS
1	Will Prothena Stock Rebound After A 13% Drop Last Week?
2	What’s Next For Prothena Stock After A 9% Rise This Week?
3	ARTICLES
4	Prothena Stock Jumped 9.5% in a Week, What Now?
5	Day 5 of Gains Streak for Prothena Stock with 19% Return (vs. 13% YTD) [1/27/2025]
6	Day 0 of Loss Streak for Prothena Stock with 0% Return (vs. 13% YTD) [1/26/2025]
7	Day 5 of Gains Streak for Prothena Stock with 19% Return (vs. 13% YTD) [1/25/2025]
8	Day 0 of Loss Streak for Prothena Corp Stock with 0% Return (vs. -55% YTD) [12/2/2024]
9	Day 0 of Loss Streak for Prothena Corp Stock with 0% Return (vs. -56% YTD) [11/30/2024]
10	Prothena vs. S&P500 Correlation
11	Prothena Price Volatility
12	Day 5 of Loss Streak for Prothena Corporation Stock with -26% Return (vs. -31% YTD) [2/6/2024]
13	Day 1 of Gains Streak for Prothena Corporation Stock with 0.04% Return (vs. -44% YTD) [10/27/2023]

Trade Ideas

Select past ideas related to PRTA. For more, see Trefis Trade Ideas.

Unique Key	Date	Ticker	Company	Category	Trade Strategy	6M Fwd Rtn	12M Fwd Rtn	12M Max DD
GDRX_10312025_Dip_Buyer_High_FCF_Yield_ExInd_DE_RevG	10312025	GDRX	GoodRx	Dip Buy	DB \| 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	-1.8%	-1.8%	-1.8%
DXCM_10312025_Monopoly_xInd_xCD_Getting_Cheaper	10312025	DXCM	DexCom	Monopoly	MY \| Getting CheaperMonopoly-Like with P/S Decline Large cap with monopoly-like margins or cash flow generation and getting cheaper based on P/S multiple	3.8%	3.8%	0.0%
ACHC_10242025_Dip_Buyer_ValueBuy	10242025	ACHC	Acadia Healthcare	Dip Buy	DB \| P/E OPMDip Buy with Low PE and High Margin Buying dips for companies with tame PE and meaningfully high operating margin	-8.9%	-8.9%	-8.9%
PBH_10102025_Dip_Buyer_ValueBuy	10102025	PBH	Prestige Consumer Healthcare	Dip Buy	DB \| P/E OPMDip Buy with Low PE and High Margin Buying dips for companies with tame PE and meaningfully high operating margin	-0.7%	-0.7%	-1.2%
REGN_10032025_Dip_Buyer_ValueBuy	10032025	REGN	Regeneron Pharmaceuticals	Dip Buy	DB \| P/E OPMDip Buy with Low PE and High Margin Buying dips for companies with tame PE and meaningfully high operating margin	7.0%	7.0%	-7.0%

Unique Key	Date	Ticker	Company	Category	Trade Strategy	6M Fwd Rtn	12M Fwd Rtn	12M Max DD
GDRX_10312025_Dip_Buyer_High_FCF_Yield_ExInd_DE_RevG	10312025	GDRX	GoodRx	Dip Buy	DB \| 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	-1.8%	-1.8%	-1.8%
DXCM_10312025_Monopoly_xInd_xCD_Getting_Cheaper	10312025	DXCM	DexCom	Monopoly	MY \| Getting CheaperMonopoly-Like with P/S Decline Large cap with monopoly-like margins or cash flow generation and getting cheaper based on P/S multiple	3.8%	3.8%	0.0%
ACHC_10242025_Dip_Buyer_ValueBuy	10242025	ACHC	Acadia Healthcare	Dip Buy	DB \| P/E OPMDip Buy with Low PE and High Margin Buying dips for companies with tame PE and meaningfully high operating margin	-8.9%	-8.9%	-8.9%
PBH_10102025_Dip_Buyer_ValueBuy	10102025	PBH	Prestige Consumer Healthcare	Dip Buy	DB \| P/E OPMDip Buy with Low PE and High Margin Buying dips for companies with tame PE and meaningfully high operating margin	-0.7%	-0.7%	-1.2%
REGN_10032025_Dip_Buyer_ValueBuy	10032025	REGN	Regeneron Pharmaceuticals	Dip Buy	DB \| P/E OPMDip Buy with Low PE and High Margin Buying dips for companies with tame PE and meaningfully high operating margin	7.0%	7.0%	-7.0%

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Peer Comparisons for Prothena

Financials

	PRTA	VRTX	APM	BBOT	GDTC	HIND	Median
Name	Prothena	Vertex P.	Aptorum	BridgeBi.	CytoMed .	Vyome
Mkt Price	10.26	421.67	1.41	12.10	1.99	6.17	8.21
Mkt Cap	0.6	108.2	-	-	-	-	54.4
Rev LTM	10	11,419	-	0	-	-	10
Op Inc LTM	-249	-199	-	-93	-	-	-199
FCF LTM	-193	3,500	-	-60	-	-	-60
FCF 3Y Avg	-141	1,984	-	-	-	-	922
CFO LTM	-193	3,846	-	-60	-	-	-60
CFO 3Y Avg	-140	2,324	-	-	-	-	1,092

Growth & Margins

	PRTA	VRTX	APM	BBOT	GDTC	HIND	Median
Name	Prothena	Vertex P.	Aptorum	BridgeBi.	CytoMed .	Vyome
Rev Chg LTM	-95.2%	10.5%	-	-	-	-	-42.4%
Rev Chg 3Y Avg	40.7%	11.0%	-	-	-	-	25.9%
Rev Chg Q	-96.7%	12.1%	-	-	-	-	-42.3%
QoQ Delta Rev Chg LTM	-92.5%	2.9%	-	-	-	-	-44.8%
Op Mgn LTM	-2,407.9%	-1.7%	-	-	-	-	-1,204.8%
Op Mgn 3Y Avg	-916.8%	26.5%	-	-	-	-	-445.2%
QoQ Delta Op Mgn LTM	-2,307.4%	2.0%	-	-	-	-	-1,152.7%
CFO/Rev LTM	-1,863.1%	33.7%	-	-	-	-	-914.7%
CFO/Rev 3Y Avg	-710.5%	22.5%	-	-	-	-	-344.0%
FCF/Rev LTM	-1,864.8%	30.6%	-	-	-	-	-917.1%
FCF/Rev 3Y Avg	-712.1%	19.2%	-	-	-	-	-346.4%

Valuation

	PRTA	VRTX	APM	BBOT	GDTC	HIND	Median
Name	Prothena	Vertex P.	Aptorum	BridgeBi.	CytoMed .	Vyome
Mkt Cap	0.6	108.2	-	-	-	-	54.4
P/S	53.4	9.5	-	-	-	-	31.4
P/EBIT	-2.2	24.7	-	-	-	-	11.2
P/E	-1.8	29.8	-	-	-	-	14.0
P/CFO	-2.9	28.1	-	-	-	-	12.6
Total Yield	-54.9%	3.4%	-	-	-	-	-25.7%
Dividend Yield	0.0%	0.0%	-	-	-	-	0.0%
FCF Yield 3Y Avg	-23.9%	2.1%	-	-	-	-	-10.9%
D/E	0.0	0.0	-	-	-	-	0.0
Net D/E	-0.7	-0.0	-	-	-	-	-0.3

Returns

	PRTA	VRTX	APM	BBOT	GDTC	HIND	Median
Name	Prothena	Vertex P.	Aptorum	BridgeBi.	CytoMed .	Vyome
1M Rtn	3.4%	4.6%	-37.3%	-2.1%	-1.0%	12.0%	1.2%
3M Rtn	45.9%	12.5%	0.7%	-	10.6%	-	11.5%
6M Rtn	39.6%	-6.3%	64.9%	-	-13.1%	-	16.6%
12M Rtn	-37.7%	-10.8%	-1.4%	-	-19.9%	-	-15.3%
3Y Rtn	-81.2%	36.5%	-78.8%	-	-	-	-78.8%
1M Excs Rtn	3.6%	4.2%	-39.7%	-3.9%	-6.2%	17.1%	-0.2%
3M Excs Rtn	22.8%	2.6%	2.6%	-	1.4%	-	2.6%
6M Excs Rtn	18.8%	-27.1%	44.1%	-	-33.9%	-	-4.1%
12M Excs Rtn	-58.3%	-30.1%	-20.1%	-	-36.1%	-	-33.1%
3Y Excs Rtn	-157.1%	-39.2%	-150.9%	-	-	-	-150.9%

Financials

Annual
Quarterly

$ Mil \| FY: 12/31	LTM	2024	2023	2022	2021	2020	2019
Period End	6/30/2025	12/31/2024	12/31/2023	12/31/2022	12/31/2021	12/31/2020	12/31/2019
Filing Date	8/4/2025	2/27/2025	2/22/2024	2/28/2023	2/25/2022	2/26/2021	3/3/2020
Key Financials
Total Revenue	10	135	91	54	201	1	1
EBITDA	-248	-154	-190	-131	73	-111	-79
Operating Income	-249	-155	-191	-132	72	-113	-86
Net Income	-303	-122	-147	-117	67	-111	-78
EPS	-5.64	-2.27	-2.76	-2.47	1.51	-2.78	-1.95
Growth Rates
Total Revenue Growth	-95.2%	47.9%	69.5%	-73.1%	23414.3%	4.8%	-14.8%
EBITDA Growth	-174.4%	19.2%	-45.3%	-279.0%	165.7%	-40.9%	47.1%
Operating Income Growth	-172.6%	19.1%	-45.2%	-282.8%	163.8%	-31.5%	39.9%
Net Income Growth	-494.9%	16.8%	-25.7%	-274.6%	160.3%	-43.1%	50.1%
Margins
EBITDA Margin	-2399.2%	-113.7%	-208.1%	-242.7%	36.4%	-13038.7%	-9697.5%
Operating Income Margin	-2407.9%	-114.4%	-209.1%	-244.1%	35.9%	-13216.2%	-10535.4%
Net Income Margin	-2929.3%	-90.5%	-160.9%	-217.0%	33.4%	-13029.8%	-9542.6%
Cash & Debt
Total Cash	371	471	619	710	579	295	376
Total Debt	10	11	12	6	12	18	23
Net Debt / (Cash)	-362	-461	-607	-704	-567	-278	-353
Cash Flows
Net Cash from Operations	-193	-150	-134	-109	93	-80	-53
Free Cash from Operations	-193	-150	-137	-109	92	-81	-54
Returns to Shareholders
Dividends	0	-0	-0	-0	-0	-0	-0
Share Repurchases	0	0	-0	-0	-0	-0	-0

$ Mil \| FY: 12/31	2025Q2	2025Q1	2024Q4	2024Q3	2024Q2	2024Q1	2023Q4	2023Q3	2023Q2	2023Q1	2022Q4	2022Q3
Period End	6/30/2025	3/31/2025	12/31/2024	9/30/2024	6/30/2024	3/31/2024	12/31/2023	9/30/2023	6/30/2023	3/31/2023	12/31/2022	9/30/2022
Filing Date	8/4/2025	5/8/2025	2/27/2025	11/12/2024	8/8/2024	5/8/2024	2/22/2024	11/2/2023	8/3/2023	5/4/2023	2/28/2023	11/3/2022
Key Financials Quarterly
Total Revenue	4	3	2	1	132	0	0	85	4	2	50	2
Ebitda	-52	-65	-65	-66	59	-81	-78	11	-66	-56	-0	-46
Operating Income	-52	-66	-65	-67	58	-82	-79	10	-67	-56	-0	-50
Net Income	-126	-60	-58	-59	67	-72	-67	22	-55	-47	6	-46
EPS	-2.34	-1.12	-1.08	-1.10	1.24	-1.34	-1.26	0.41	-1.03	-0.89	0.13	-0.97
Key Financials TTM
Total Revenue TTM	10	138	135	133	217	89	91	141	58	55	54	5
Ebitda TTM	-248	-138	-154	-167	-90	-215	-190	-112	-168	-145	-127	-160
Operating Income TTM	-249	-139	-155	-168	-91	-216	-191	-113	-173	-150	-132	-165
Net Income TTM	-303	-110	-122	-132	-51	-172	-147	-73	-141	-128	-117	-156
Growth Rates Quarterly
Total Revenue Growth	-96.7%	5556.0%	571.8%	-98.9%	3184.7%	-97.7%	-99.4%	5494.3%	206.3%	88.1%	4159.6%	-98.9%
EBITDA Growth	-188.4%	19.6%	17.3%	-729.1%	188.4%	-44.9%	-108565.3%	123.1%	-54.1%	-48.6%	99.8%	-141.2%
Operating Income Growth	-189.1%	19.6%	17.3%	-745.3%	187.8%	-44.7%	-108948.6%	120.5%	-53.9%	-48.4%	99.8%	-146.1%
Net Income Growth	-288.0%	16.7%	14.1%	-369.3%	222.5%	-54.1%	-1162.8%	147.9%	-32.4%	-29.1%	119.1%	-141.9%
Margins Quarterly
EBITDA Margin	-1171.5%	-2311.1%	-3046.4%	-6833.7%	44.4%	-162626.0%	-24759.2%	12.4%	-1649.2%	-2587.6%	-0.1%	-3011.5%
Operating Income Margin	-1176.6%	-2319.0%	-3056.9%	-6857.0%	44.2%	-163056.0%	-24846.5%	12.1%	-1654.7%	-2596.8%	-0.1%	-3317.9%
Net Income Margin	-2845.4%	-2128.5%	-2729.9%	-6082.6%	50.7%	-144478.0%	-21353.2%	25.8%	-1358.4%	-2160.6%	12.7%	-3016.7%
Cash & Debt
Total Cash	371	418	471	519	564	547	619	671	659	686	710	496
Total Debt	10	10	11	11	12	12	12	11	3	5	6	8
Net Debt / (Cash)	-362	-408	-461	-508	-552	-534	-607	-660	-656	-681	-704	-488
Cash Flows Quarterly
FCF from Operations	-46	-53	-48	-45	16	-73	-51	10	-45	-47	-5	-31
Cash Flows TTM
FCF from Operations TTM	-193	-130	-150	-153	-99	-159	-134	-88	-129	-119	-109	-126
Returns to Shareholders Quarterly
Dividends	0	0	0	0	0	0	0	0	0	0	0	0
Share Repurchases	0	0	0	0	0	0	-0	-0	-0	0	-0	-0
Return on Invested Capital (ROIC) Quarterly
ROIC	-16.6%	-21.6%	-22.4%	-24.5%	23.0%	-31.0%	-32.1%	4.7%	-28.7%	-26.3%	-0.0%	-25.2%
Return on Invested Capital (ROIC) TTM
ROIC TTM	-19.9%	-11.1%	-13.0%	-14.8%	-7.5%	-19.7%	-18.7%	-11.0%	-18.4%	-17.3%	-16.3%	-21.0%

Price Behavior

Price Behavior

Market Price	$10.26
Market Cap ($ Bil)	0.6
First Trading Date	12/21/2012
Distance from 52W High	-44.1%
	50 Days	200 Days
DMA Price	$9.37	$9.60
DMA Trend	down	up
Distance from DMA	9.4%	6.9%
	3M	1YR
Volatility	51.1%	76.7%
Downside Capture	48.94	113.72
Upside Capture	223.23	47.11
Correlation (SPY)	29.2%	18.0%

PRTA Betas & Captures as of 10/31/2025

	1M	2M	3M	6M	1Y	3Y
Beta	1.94	1.25	1.31	0.60	0.72	1.08
Up Beta	2.27	2.29	1.65	-0.86	0.03	0.67
Down Beta	0.63	1.05	1.05	1.89	1.55	1.62
Up Capture	324%	220%	261%	91%	35%	32%
Bmk +ve Days	14	27	37	74	145	425
Stock +ve Days	12	23	33	65	126	357
Down Capture	242%	19%	23%	85%	110%	108%
Bmk -ve Days	9	17	28	53	106	327
Stock -ve Days	11	19	29	58	120	388

[1] Upside and downside betas calculated using positive and negative benchmark daily returns respectively

1Y 5Y 10Y

Based On 1-Year Data

		Comparison of PRTA With Other Asset Classes (Last 1Y)
	PRTA	Sector ETF	Equity	Gold	Commodities	Real Estate	Bitcoin
Annualized Return	-43.3%	-0.7%	17.5%	40.7%	2.0%	-4.1%	45.5%
Annualized Volatility	76.5%	17.0%	19.7%	19.9%	16.3%	18.0%	36.9%
Sharpe Ratio	-0.41	-0.21	0.70	1.60	-0.06	-0.38	0.80
Correlation With Other Assets		19.0%	18.8%	-0.6%	1.6%	8.6%	6.9%

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)
	PRTA	Sector ETF	Equity	Gold	Commodities	Real Estate	Bitcoin
Annualized Return	-2.2%	8.1%	16.4%	15.1%	12.9%	6.6%	50.5%
Annualized Volatility	83.9%	14.6%	17.2%	15.6%	18.9%	19.1%	49.2%
Sharpe Ratio	0.31	0.39	0.78	0.77	0.57	0.26	0.77
Correlation With Other Assets		28.3%	29.7%	6.2%	9.2%	24.2%	15.1%

Based On 10-Year Data

		Comparison of PRTA With Other Asset Classes (Last 10Y)
	PRTA	Sector ETF	Equity	Gold	Commodities	Real Estate	Bitcoin
Annualized Return	-15.0%	9.2%	14.5%	12.5%	5.3%	5.1%	80.1%
Annualized Volatility	76.9%	16.7%	18.0%	14.7%	17.7%	20.9%	56.2%
Sharpe Ratio	0.15	0.45	0.69	0.69	0.23	0.22	0.97
Correlation With Other Assets		32.8%	31.9%	2.6%	13.2%	22.0%	9.5%

Short Interest

Short Interest: As Of Date	10152025
Short Interest: Shares Quantity	3,857,015
Short Interest: % Change Since 9302025	0.3%
Average Daily Volume	718,695
Days-to-Cover Short Interest	5.37
Basic Shares Quantity	53,827,000
Short % of Basic Shares	7.2%

Returns Analyses

	Title
0	Prothena Stock Jumped 9.5% in a Week, What Now?
1	Prothena Stock Return Comparison
2	[10/7/2021] Prothena Corporation plc (PRTA) Stock Price Forecast: AI Forecasts PRTA Stock Price To Be Around $77.50 In A Month (Up 5.8%)

SEC Filings

Expand for More

Report Date	Filing Date	Filing
6302025	8042025	10-Q 6/30/2025
3312025	5082025	10-Q 3/31/2025
12312024	2272025	10-K 12/31/2024
9302024	11122024	10-Q 9/30/2024
6302024	8082024	10-Q 6/30/2024
3312024	5082024	10-Q 3/31/2024
12312023	2222024	10-K 12/31/2023
9302023	11022023	10-Q 9/30/2023
6302023	8032023	10-Q 6/30/2023
3312023	5042023	10-Q 3/31/2023
12312022	2282023	10-K 12/31/2022
9302022	11032022	10-Q 9/30/2022
6302022	8082022	10-Q 6/30/2022
3312022	5052022	10-Q 3/31/2022
12312021	2252022	10-K 12/31/2021
9302021	11042021	10-Q 9/30/2021

Insider Activity

Expand for More

	Owner	Title	Filing Date	Action	Price	Shares	Transacted Value	Value of Held Shares	Form
0	EcoR1 Capital, LLC		5062025	Sell	8.36	3,317,938	27,744,929	69,123,978	Form

Industry Resources

Health Care Resources

U.S. National Library of Medicine

Health Data Management

FDA Tracker

Biotechnology Resources

Fierce Biotech

Nature Biotechnology

Genetic Engineering & Biotechnology News

Biotechnology Innovation Organization

BioWorld

BioTechniques

HBS Biotechnology Publications

External Quote Links

0	Y Finance	Barrons
1	TradingView	Morningstar
2	SeekingAlpha	ValueLine
3	Motley Fool	Robinhood
4	CNBC	Etrade
5	MarketWatch	Unusual Whales
6	YCharts	Perplexity Finance
7	FinViz

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Prothena (PRTA)

Market Price (11/5/2025): $10.265 | Market Cap: $552.5 MilSector: Health Care | Industry: Biotechnology

Prothena (PRTA)

Market Price (11/5/2025): $10.265Market Cap: $552.5 MilSector: Health CareIndustry: Biotechnology

Market Valuation & Key Metrics

PRTA Stock

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Based On 1-Year Data

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Market Price (11/5/2025): $10.265 | Market Cap: $552.5 Mil
Sector: Health Care | Industry: Biotechnology

Market Price (11/5/2025): $10.265
Market Cap: $552.5 Mil
Sector: Health Care
Industry: Biotechnology