Prothena stock

PRTANASDAQ

Prothena Corporation plc, HealthcareISIN IE00B91XRN20

$8.23▼ $0.50 (−5.7%)Closing price of 12 Nov 2026

43Score 43 out of 100, Weak

Turn on early warning

Price and trend

63 / 100

Price history

−24% in one year

The chart shows daily closes over 14 years, adjusted for stock splits and without dividends. Click into the chart to set a price alert at that price.

TrendBelow the 200-day line, momentum normal

Long-term trend

Below the 200-day line: the price is 10% below it.

Trend change

Since July 2026 the 50-day line has been below the 200-day line; the trend has turned down.

Momentum

Normal: the price is neither overheated nor sold off (RSI 50).

Distance to the high

The price is 28% below its 52-week high. Largest decline in 14 years: 94% (September 2021 to May 2025).

Chart figures for advanced users

SMA 50$8.57: Average price of the last 50 trading days, shows the short-term trend.
SMA 200$9.18: Average price of the last 200 trading days, shows the long-term trend.
RSI (14)50: Relative strength over the last 14 days on a scale from 0 to 100. Above 70 the price counts as overheated, below 30 as sharply fallen.
MACDabove the signal line: Compares a fast and a slow price average. Above its signal line momentum is rising, below it momentum is fading.
Support$7.89: The lowest closing price of the last twelve months.
Resistance$11.51: The highest closing price of the last twelve months.

What would $1,000 in Prothena have become?Return triangle for Prothena

Market cap

$448.28M

Div. yield

no dividend

Loss

Loss expected

Fair value

no data

Snapshot

Computed from the data by fixed rules, no AI

Prothena Corporation plc belongs to the Biotechnology industry (Ireland) and, with a market value of $422.61M, is number 256 of 296 companies in its industry on MEQIRI.
In fiscal 2025 it reported revenue of $9.68M (down 92.8% year on year) and a loss of $244.09M.
For fiscal 2026, analysts expect on average revenue of $72.42M (up 647.9%) and adjusted earnings per share of −$0.02.

MEQIRI Score 43 out of 100 (Weak): rank 509 of 714 in Healthcare, median 53.

In plain words

The numbers on this page in plain words, written by an AI

Strengths

Growing faster than its industryRevenue up 62.6% a year since 2020, Biotechnology median 19.7%.Growth 70
More cash than debtCash $271.37M, financial debt $6.26M.Stability 74

Weaknesses

DilutionShare count up 35% since 2020.Capital allocation 18
Loss-makingLoss of $23.96M over the last 12 months.Fundamentals 17
Negative free cash flowFree cash flow −$32.17M over the last 12 months.Fundamentals 17

43/ 100

Score

Weak

Its standout strengths are stability and growth, while capital allocation and fundamentals hold the score back.

Daily figure as of 12 Nov 2026

How the score is calculated

Score overview

Score since yesterday from 41 to 43.

One-off effect in revenue

In the quarter to 31 Mar 2026, revenue of $51.08M was about 23 times the usual level. P/E, margin, growth and score for the last twelve months depend on it.

Fundamental quality fluctuates.

Profit consistency10% of years

Cash conversion (free cash flow to earnings, 12 months)not measured

ROIC (12 months)−11.1%

Positive free cash flow10% of years

How this category is measured

Score history

The full history of up to 20 years comes with MEQIRI Pro.

See plans

Valuation

Valuation signal

not measured

Price

$8.73

Fair value

not computable

Gap to fair value

no data

Closing price of 11 Nov 2026, used by the daily score.

No fair value can be calculated for this stock, so the signal follows the valuation grade.

Valuation metrics

no data

Fair value (model)

no data

No fair value can be calculated for this stock from the available figures.

Calculate with your own assumptions

Company performance

This shows several years of history with an automatic assessment.

Revenue

16 years

In the quarter to 30 Sep 2026, revenue fell 74.3% on the same quarter a year earlier. Revenue has grown strongly since 2010, at around 15% per year.

Margins

16 years

Gross margin
Operating margin
Net margin

In fiscal 2025: gross 62%, operating −1906%, net −2521%. Last 12 months: net −45%.

Debt & balance sheet

latest quarter

0.02

no data

23.95

Cash & equivalents

$271.37M

Debt is low; no interest coverage is reported.

Earnings

Next earnings: 18 Feb 2027in 98 days
Last reported: 5 Nov 2026EPS reported −$0.32 (expected −$0.23)below expectations

Analyst estimates

Analysts have cut their 2026 earnings estimate by 120.5% since 15 Oct 2026. Falling estimates often precede bad news.

Fiscal 20264 analysts

Earnings per share: −$0.02−120.5%
Revenue: $72.42M−12.4%

Fiscal 20275 analysts

Earnings per share: −$1.02+0.7%
Revenue: $24.54M0.0%

MEQIRI has stored the estimates since 15 Oct 2026. Until 30 days are available, the card shows the change since that day. Mean estimate according to Financial Modeling Prep. No price target and no recommendation.

Insiders1 insider bought and 2 insiders sold in the last 6 months

Insiders

Open-market purchases and sales by executives, board members and major holders

All insider purchases

One insider bought on the open market in the last 6 months, $13.27M in total. 2 insiders sold, $135,975 in total.

Sales say less than purchases: many insiders sell on a fixed plan, for taxes or to diversify.

Scully William PPurchase
9 Nov 2026, Major holder
Shares
140,000
Price
$8.53
Value
$1.19M
Scully William PPurchase
23 Oct 2026, Major holder
Shares
50,000
Price
$8.07
Value
$403,525
Scully William PPurchase
22 Oct 2026, Major holder
Shares
100,000
Price
$8.19
Value
$818,520

Show 18 more

Scully William PPurchase
14 Oct 2026, Major holder
Shares
10,000
Price
$8.46
Value
$84,569
Scully William PPurchase
13 Oct 2026, Major holder
Shares
100,000
Price
$8.35
Value
$835,480
Scully William PPurchase
8 Oct 2026, Major holder
Shares
90,000
Price
$8.57
Value
$770,904
Scully William PPurchase
7 Oct 2026, Major holder
Shares
125,000
Price
$8.40
Value
$1.05M
Scully William PPurchase
2 Oct 2026, Major holder
Shares
100,000
Price
$8.57
Value
$857,240
Scully William PPurchase
29 Sept 2026, Major holder
Shares
162,000
Price
$8.68
Value
$1.41M
Scully William PPurchase
28 Sept 2026, Major holder
Shares
103,500
Price
$8.60
Value
$889,872
Scully William PPurchase
18 Sept 2026, Major holder
Shares
100,000
Price
$8.43
Value
$843,460
Scully William PPurchase
2 Sept 2026, Major holder
Shares
27,000
Price
$9.47
Value
$255,739
Scully William PPurchase
20 Aug 2026, Major holder
Shares
50,000
Price
$8.79
Value
$439,430
Scully William PPurchase
7 Aug 2026, Major holder
Shares
37,500
Price
$8.62
Value
$323,220
Kingston Anne EvansSale
29 Jul 2026, Chief Strategy Officer
Shares
7,662
Price
$8.47
Value
$64,919
Isaacs Michael JohnSale
29 Jul 2026, General Counsel & Company Sec.
Shares
8,386
Price
$8.47
Value
$71,055
Scully William PPurchase
16 Jun 2026, Major holder
Shares
20,000
Price
$7.90
Value
$157,990
Scully William PPurchase
11 Jun 2026, Major holder
Shares
125,000
Price
$8.17
Value
$1.02M
Scully William PPurchase
4 Jun 2026, Major holder
Shares
50,000
Price
$9.31
Value
$465,295
Scully William PPurchase
2 Jun 2026, Major holder
Shares
50,000
Price
$9.43
Value
$471,300
Scully William PPurchase
22 May 2026, Major holder
Shares
100,000
Price
$9.81
Value
$981,300

Trade date	Person	Type	Shares	Price	Value	Holding
9 Nov 2026	Scully William PMajor holder	Purchase	140,000	$8.53	$1.19M	977,000(+17%)
23 Oct 2026	Scully William PMajor holder	Purchase	50,000	$8.07	$403,525	1,187,000(+4%)
22 Oct 2026	Scully William PMajor holder	Purchase	100,000	$8.19	$818,520	1,137,000(+10%)
14 Oct 2026	Scully William PMajor holder	Purchase	10,000	$8.46	$84,569	1,037,000(+1%)
13 Oct 2026	Scully William PMajor holder	Purchase	100,000	$8.35	$835,480	1,027,000(+11%)
8 Oct 2026	Scully William PMajor holder	Purchase	90,000	$8.57	$770,904	529,000(+21%)
7 Oct 2026	Scully William PMajor holder	Purchase	125,000	$8.40	$1.05M	439,000(+40%)
2 Oct 2026	Scully William PMajor holder	Purchase	100,000	$8.57	$857,240	314,000(+47%)
29 Sept 2026	Scully William PMajor holder	Purchase	162,000	$8.68	$1.41M	214,000(+312%)
28 Sept 2026	Scully William PMajor holder	Purchase	103,500	$8.60	$889,872	187,000(+124%)
18 Sept 2026	Scully William PMajor holder	Purchase	100,000	$8.43	$843,460	927,000(+12%)
2 Sept 2026	Scully William PMajor holder	Purchase	27,000	$9.47	$255,739	827,000(+3%)
20 Aug 2026	Scully William PMajor holder	Purchase	50,000	$8.79	$439,430	800,000(+7%)
7 Aug 2026	Scully William PMajor holder	Purchase	37,500	$8.62	$323,220	873,500(+4%)
29 Jul 2026	Kingston Anne EvansChief Strategy Officer	Sale	7,662	$8.47	$64,919	55,782
29 Jul 2026	Isaacs Michael JohnGeneral Counsel & Company Sec.	Sale	8,386	$8.47	$71,055	35,745
16 Jun 2026	Scully William PMajor holder	Purchase	20,000	$7.90	$157,990	756,000(+3%)
11 Jun 2026	Scully William PMajor holder	Purchase	125,000	$8.17	$1.02M	1,061,000(+13%)
4 Jun 2026	Scully William PMajor holder	Purchase	50,000	$9.31	$465,295	936,000(+6%)
2 Jun 2026	Scully William PMajor holder	Purchase	50,000	$9.43	$471,300	886,000(+6%)
22 May 2026	Scully William PMajor holder	Purchase	100,000	$9.81	$981,300	836,000(+14%)

Show 13 more

Partial trades from one filing are shown in one row, with the average price.

Source: Form 4 filings with the US Securities and Exchange Commission. Grants, option exercises, gifts and tax withholdings are hidden. Not a recommendation to buy.

What happened at Prothena5 events in recent months

What happened at Prothena

The key events of the last six months from our own data. A click takes you to the matching card.

Sector comparisonRank 509 of 714 in Healthcare

Sector comparison

714 rated companies in Healthcare

Rank 509 of 714

509/ 714

This company: 43
Sector median: 53

Categories against the sector medianMedian of 714 companies

Profitability25 (median 37)12 below the median

Growth70 (median 53)17 above the median

Fundamentals17 (median 46)29 below the median

Stability74 (median 67)7 above the median

Capital allocation18 (median 39)21 below the median

Technical analysis63 (median 70)7 below the median

Momentum42 (median 71)29 below the median

The median is the middle value: half of the companies in the sector lie above it, half below. Categories with too few comparable companies are left out.

Competitors in Biotechnology

The next larger and next smaller companies by market value

All 296 Biotechnology stocks

ETFs that hold ProthenaHeld by 5 ETFs on Xetra

ETFs that hold Prothena

Held by 5 ETFs on Xetra. Shown per index: the ETF with the largest weight.

ETF	Weight	Cost	Fund size
iShares Healthcare Innovation UCITS ETF2B78	0.03%	0.40%	€1.49B
iShares Ageing Population UCITS ETF2B77	0.03%	0.40%	€807M
iShares Nasdaq US Biotechnology UCITS ETF2B70	0.03%	0.35%	€1.21B

Show 2 more

State Street SPDR Russell 2000 U.S. Small Cap UCITS ETF (Acc)ZPRR	0.02%	0.30%	€4.22B
Xtrackers Russell 2000 UCITS ETF 1CXRS2	0.01%	0.30%	€2.17B

Holdings as reported by the funds via FMP, excluding swap ETFs (their holdings are only collateral).

Data status and sourcesWhen it was calculated, from which sources

Data status and sources

Score: Daily value of 12 Nov 2026, recalculated nightly
Price: Closing price of 12 Nov 2026
Latest annual report: Fiscal year 2025, period end 31 Dec 2025
Source: Financial statements, ratios and prices from Financial Modeling Prep (FMP), based on the company's reports. MEQIRI calculates the score and fair value from them.

Report a data error

Mandatory disclosures for this rating

Computed on 12 Nov 2026, 04:09 Berlin time; time horizon around 12 months
Rated Weak, published since 7 Nov 2026 (in the score history since 31 Aug 2022)
End-of-day prices, metrics cached for up to 24 hours
Score and fair value are estimates from a disclosed model. They are not facts and not a price target.
Produced by SSM Ventures UG (haftungsbeschränkt), responsible person Sven Brostmeyer, Managing Director, automatically according to the disclosed model.
Not investment advice. Losses up to and including a total loss are possible. Personal circumstances are not considered.

Full disclosures, methodology and data sources All ratings of the last 12 months How the score is calculated

Prothena stock

Price and trend

Price history

Snapshot

In plain words

Strengths

Weaknesses

Score overview

Score history

Valuation

Valuation signal

Valuation metrics

Company performance

Revenue

Earnings (net income)

Operating income

Earnings per share

Free cash flow

Operating cash flow

Shares outstanding

Shareholders' equity

Margins

Returns on capital

Cash and debt

Debt & balance sheet

Earnings

Analyst estimates

Insiders

What happened at Prothena

Sector comparison

Categories against the sector medianMedian of 714 companies

Competitors in Biotechnology

ETFs that hold Prothena

Data status and sources

Mandatory disclosures for this rating