Prothena (PRTA) stock

Disease therapeutics , market cap $456M

Therapeutics for brain diseases

Market cap $456M

$8.29

-2.13%

After-hours $8.29 0.00%

As of 6:57 PM ET after-hours, delayed 15+ min · Live for Pro members

Quality Score

Below Average

In its industry

#49of 92

Pharma

Checks firing

2of 14

Choppy

From 52-week high

-29.7%

Below the 200-day

PRTA's Quality Score fell 1 point on Mon, Nov 2, to 0.

Follow PRTA's news. Pro members can get an alert when Prothena files news, and see its trials, share raises, and its CEO's filings.

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We do the work for you. Every stock is scored and ranked, every 15 seconds while the market is open. Here it's 15 minutes behind. Pro members see it live.

Cash$288M in cash. One of the last four quarters brought cash in while the others used it.On Jun 30

Why is PRTA down?

Down 76% over three years while the S&P 500 rose 89%.

Revenue fell 43.6% a year, from $53.9M in fiscal 2022 to $9.7M in fiscal 2025; Acadia Pharmaceuticals' grew 27.5% a year.

Sources: Price history, Oct 30, 2026; Annual reports, Dec 31, 2025; Peers' annual reports, Oct 30, 2026; 10-K segment note, Feb 27, 2026

1 more reason, free with an account →How the business stands, the timeline, and its peers, for Pro members.

Key facts on PRTA

Key facts on PRTA
Since its 2023 high	Down 89% while sales grew 1%
Latest filing	8-K, Oct 29 Ended a material agreement

1 more reason behind PRTA's 0, free with an account →3 more reasons behind PRTA's 0, for Pro members.

PRTA in the news

ReportReports Thursday, after the close. Every 3 months, a company tells everyone how much it sold and earned. It rose after 3 of its last 4 reports, +2.2% on average. Past reports ›

Cash$288M in cash. One of the last four quarters brought cash in while the others used it.On Jun 30

PRTA catalysts

Coming up

After its last 4 reports it closed +2.2% on average, higher 3 of 4 times.

17 past catalysts since 2018, with sizes and sources, for Pro members.Get in free →

What's next for PRTA, and how long its cash lasts

Cash runway Jun 30 balance sheet

$288M in cash

One of the last four quarters brought cash in while the others used it, so an average says little about the next.

What it means: a runway is counted only when each of the last four quarters used cash.

For Pro members: the cash used each quarter, and the math.

Dilution on the horizon

Shelf registration (S-3ASR, filed Feb 22, 2024)
At-the-market share sales program (S-3ASR, filed Feb 22, 2024)

For Pro members: the amounts, and the share count against a year ago.

Insiders

Chief Strategy Officer Anne Evans Kingston sold 7,662 shares on Jul 29, under a planned sale. 1 more insider trade this year.

From Form 4: open-market buys and sales only.

Get an alert when Gene Kinney buys or sells

For Pro members: every trade, and Gene Kinney’s 8 filings and quotes.

Get an alert when PRTA files newsSee it live, free until Wednesday morning. No account. No card. Then keep going with a free account.

See every upcoming FDA date →

FDA dates in the next 60 days

Decision dates and advisory committee meetings the companies have announced in their filings, soonest first and small companies first.

DateStockDrug

In 20 daysFDA decisionIn 20 days · FDA decisionCAPRCapricor TherapeuticsDeramiocelCAPRCapricor Therapeutics · $385MDeramiocelFDA decision due (PDUFA)
In 20 daysFDA decisionIn 20 days · FDA decisionSVRASavaraMolgramostimSVRASavara · $1.0BMolgramostimFDA decision due (PDUFA)
In 50 daysFDA decisionIn 50 days · FDA decisionMLYSMineralys TherapeuticsLorundrostatMLYSMineralys Therapeutics · $1.9BLorundrostatFDA decision due (PDUFA)

11 more FDA dates and 102 trial data dates in the next 60 days, each on the FDA calendar. Pro members see whether each company's cash lasts past its date, with an optional alert before it. See all 143 dates, ranked →

Why PRTA scores 0

Below Averagefor quality, not price, 2 of 14 chart checks firingWhat the Quality Score means

+2Chart checks 2 of 14 firing right now, one point each
−3Long-term trend below a falling 200-⁠day average, down over one year, down over two years

Growth addsSales and margins against a year earlier: up to +3 for fast growth and widening margins, down to -2 when both shrink.
Volatility subtractsA daily range of 5% or more with nothing behind it (no profit or cash flow, sales shrinking, or 10% more shares outstanding with no free cash flow): -1, or -2 from 8%.
Cash flow subtracts-1 when free cash flow over the last four quarters is negative.
Insider trades adds

No effect today: Run-up, Size, Profit, Dilution, Persistence, and News.

What every line is worth, and the reason behind it, on PRTA and every other stock.Get in free →

Price, score, chart checks, and the industry rank are from a snapshot taken at 6:57 PM ET, at least 15 minutes behind. How we rank stocks.

Tested. Our top-⁠scored stocks returned 2.2x the average stock over the next month. How we tested it

Alert me when PRTA's Quality Score turns up

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Here is what Pro members see.

The same page for Pro members, on AMD
Its Quality Score and rank, the line that drives it, and the live price.
The full chart
A year of candles to start, out to the whole history, with insider trades marked and the Quality Score under the price.
Every line of the score
Price action, the company, and signals, each with its points, on PRTA and every other stock.
FDA dates, counted down
Each date in the company's words, its cash against the date, and an optional alert before it.
CEOs buying their own stock
Every CEO buy, biggest names first. Sort, filter, save the list, and set optional alerts.
Congress trades
A member's trades, newest first, each with its amount. Sort and filter the whole list.
14 chart checks, read for you
The ones firing on the stock, each in plain words, its rule a tap away.
Earnings, week by week
Who reports each day, and how each stock took its last four reports.
The market map
Every stock a box, colored by its Quality Score.
Themes, ranked live
Each theme's stocks ranked by Quality Score, live. Here, AI chips.
The top 10, every day
The ten highest Quality Scores at each close, kept day by day, week by week.
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Pick a stock, a score, a price, a filing, or a whole scan. It tells you by push or email.
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Your stocks by Quality Score, today's move, or name.
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The same account and watchlist on both, each laid out for its screen.

Prices refresh every 2.5 seconds during market hours.
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Add it to your Home Screen and it opens like an app.

PRTA has 2 of 14 chart checks firing

Trend1 of 5 shown

MA FAN 21 EMA W.EMA HH/HL 52W HI

Volume1 of 3 shown

VOL VDU U/D VOL

Tight range1 of 3 shown

ATR SQZ SQUEEZE NR7

Buying1 of 3 shown

OBV+CLOSE HI SPRING

The other 10 checks on PRTA, and all 14 on every stock.Get in free →

PRTA RSI today: 45.6, below its 50-day and 200-day averages

Not scored

Not in the Quality Score: over 20 years of tests, 2006 to 2026, they added no edge.

RSI 1445.6
Above 30, below 50.
MACD (12, 26, 9)Above signal
Crossed above its signal line 5 sessions ago.
50-day average$8.74
The price is 5.1% below it.
200-day average$9.23
The price is 10.2% below it.
50/200 crossDeath cross
The 50-day crossed below the 200-day on Jul 6.
ADX 1411.0
Under 25, with +DI above -DI.
Support$8.23
Swing low from Feb 5, 0.7% below the price.
Resistance$8.99
Swing high from Sep 30, 8.4% above the price.
52-week high$11.80
From May 8, 42.3% above the price.
52-week low$7.73
From Jun 11, 6.8% below the price.
Chart patternNone
No triangle, channel, or wedge in the last year.
Bollinger Bands (20, 2)Inside
The bands run from $7.93 to $9.00.
Volume0.8x
Against its 20-day average, for the time of day.

The deep dive on PRTA

What it does and how it makes money2 findings"These options include building our own internal sales force … whereby another pharmaceutical or biotechnology company sells and markets the product and pays us a royalty on sales." (10-K for fiscal 2025)SEC filing · Feb 27, 2026
Where it stands1 findingFor Pro members1 finding on where PRTA stands: its cash, debt, and share count, for Pro members
Who holds and trades it2 findingsInsiders bought $8.98M of shares on the open market in 90 days, with no sales; the largest, 10% owner William P. Scully, bought $1.41M on Sep 29, 2026.Form 4, filed Sep 30, 2026

3 more findings on PRTA, each with its source, for Pro membersGet in free →

How PRTA ranks in Pharma

PRTA is #49 of 92 by Quality Score.

How PRTA ranks in Pharma
1	ABBVAbbVie	6/14	21
2	LLYEli Lilly	6/14	20
3	GMABGenmab	5/14	18
	PHVSPharvaris		Open for its score
	PRGOPerrigo		Open for its score
	QDELQuidelOrtho		Open for its score
	QUREuniQure		Open for its score
49	PRTAProthena	2/14	0

When does PRTA report earnings, and what happens after?

Reports Thu Nov 5, after the close (in 3 days). Confirmed.

What an earnings report is: every 3 months, a company tells everyone how much it sold and earned. We read the figures, the outlook, and how the stock moved after.

What PRTA reported on Aug 6, 2026

The quarter

The figures are not read from the release yet.

“This decrease in cash position is primarily driven by cash utilized as part of the share repurchase program of approximately $12 million between May 1, 2026 and July 30, 2026.”

The filing on EDGAR

Where the sales came from

PRTA's results filing gives no sales by line in a table we read.

The outlook

The outlook the company gave, by period
Measure	Figure
Full year 2026
Cash, cash equivalents and restricted cash at year end	$259Mcut

Figures as filed (SEC filing, Aug 6)

1 more outlook line, for Pro members.

The numbers

Market value: $456M; today
Sales: $54.5M; up 427% on the year

Sales fell 44% a year over 3 years, fiscal 2022 to 2025.

Its share count grew 6.2% a year over 5 years.

2 more figures, for Pro members.

No analyst estimates on Breakaway: every figure here is filed.

The whole report on PRTA: every line of its sales, every outlook beside the one it replaced, and the company's words, for Pro members.Get in free →

-0.1%+2.0%+2.1%

Feb 19May 7Aug 6

Reported	When	Gap	Reaction	5 sessions
Aug 6, 2026After close	After close	-0.5%	+2.1%	+5.8%
May 7, 2026After close	After close	+4.6%	+2.0%	-6.3%
Feb 19, 2026After close	After close	+3.9%	-0.1%	-4.3%

PRTA closed higher after 3 of its last 4 reports.

All 4 reports, and PRTA's Quality Score going into each

Everyone reporting earnings this week

PRTA sales and profit by year

Sales and profit by year

Sales grew in four of the last seven years, to $9.7M in 2025. It made a profit in one of the eight years.

PRTA share count over time

Shares: 3.1% fewer than a year ago (to Jun 30).

Shares of PRTA outstanding, as filed
Shares outstanding	As of
51.3M	Jul 30, 2026
52.4M	Apr 30, 2026
53.8M	Feb 20, 2026
53.8M	Oct 31, 2025

Offerings, shelves, and splits of PRTA, from its filings
From its filings	Filed
Registered shares for a later sale (S-3ASR)	Feb 22, 2024

Insiders trading PRTA

PRTA insider trades

One insider bought $12.1M across 19 filings in the last 6 months. No open-⁠market sales on record. The newest:

BuyWilliam P. Scully$819K10% ownerat $8.19 on Oct 22, filed Oct 26

BuyWilliam P. Scully10% owner$819Kat $8.19 on Oct 22, filed Oct 26

All 19 insider filings on PRTA from the last six months, for Pro members.Get in free →

All PRTA insider trades

PRTA's officers and directors

Officers and directors with a Form 4 in the last 12 months.

Gene G. KinneyPresident and CEO
Tran NguyenChief Strategy Officer and CFO
Anne Evans KingstonChief Strategy Officer · 1 trade
Michael John IsaacsGeneral Counsel & Company Sec. · 1 trade
Brandon S. SmithChief Operating Officer
Chad J. SwansonChief Development Officer
Karin L. WalkerChief Accounting Officer
Wagner M. ZagoChief Scientific Officer

See insider trades by person

About Prothena

Prothena Corp PLC is a late-stage clinical biotechnology company that focuses on protein dysregulation and a pipeline of investigational therapeutics with the potential to change the course of devastating neurodegenerative and rare and peripheral amyloid diseases. Prothena is developing and applying its proprietary CYTOPE technology to target a broad spectrum of intracellular disease pathways in the brain and periphery. The company's pipeline includes both wholly-owned and partnered programs like Prasinezumab, Coramitug (PRX004), BMS-986446 (PRX005), PRX019, TDP-43 CYTOPE, and PRX012-TfR, being developed for the potential treatment of Parkinson's disease, ATTR amyloidosis with cardiomyopathy, Alzheimer's disease, Amyotrophic lateral sclerosis (ALS), and other neurodegenerative diseases.

67 employeesDublin 2prothena.com

What Prothena says it competes with

“The pharmaceutical industry is highly competitive.”

From its annual report, SEC filing · Feb 27, 2026

2 more sentences and what it says it does, for Pro membersGet in free →

PRTA's score card

Prothena (PRTA): Quality Score 0, Below Average, #49 of 92 in Pharma, with its price, on Breakaway — The picture a link to this page shows when it is shared.

Pro members see every line of every stock's score.

What would turn PRTA's score around: 8 things
4 more filings explained, a plain line each
Real-⁠time prices, no delay

BreakawayOct 26William P. Scully bought PRTA$819K at $8.19, filed Oct 26

Alerts are optional.

See PRTA's 14 chart checks

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Straight Answers

As of Nov 2, 2026: PRTA's Quality Score is 0 (Below Average), #49 of 92 in Pharma. Insiders bought $12.1M in the last 6 months (Form 4).

Is PRTA a good stock to buy? What its Quality Score says

PRTA scores 0 today, which Breakaway calls Below Average. It is #49 of 92 in Pharma by Quality Score, with 2 of 14 chart checks firing. Down 76% over three years while the S&P 500 rose 89%. Breakaway does not say whether to buy any stock: the score does not know your situation, and it is not a recommendation to buy or sell anything. Please do your own research.

What is PRTA's Quality Score?

PRTA scores 0 today, which Breakaway calls Below Average (0 to 5). That is #49 of 92 in Pharma by Quality Score. The score adds up the chart checks, the trend, the company's filed sales, its profits, the news, insider trades, and Congress trades. The section above lists the lines behind PRTA's 0.

Are insiders buying PRTA?

One insider bought $12.1M across 19 filings in the last 6 months. No open-⁠market sales on record. The newest is William P. Scully, 10% owner, who bought $819K on Oct 22. Every filing, with the scored weight, for Pro members.

Are the prices delayed?

Only on the public pages, which run at least 15 minutes behind. Pro members, and anyone on a guest pass, see real-time prices: the scanner refreshes every 15 seconds, and your watchlist every few seconds, pre-market and after hours included.