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PRTA Stock Forecast: Prothena Corp. Plc Price Predictions for 2026-2027

Last close, 14 Sept 2026
$8.86
−0.78% on the day

The 6 Wall Street analysts covering Prothena Corp. Plc hold a median 12-month price target of $20 — +125.7% from the last close. Ticker Nerd's systematic factor model, run across ~4,600 US stocks, ranks it 98 of 100 as at 14 Sept 2026 — among the strongest tenth. Here, the model and the Street point the same way.

Market cap
$454.8M
Ticker Nerd rank
98 / 100
Median analyst target
$20
Analysts covering
6
Revenue$1.0M−77.1% y/y
Operating income−$18.7M
Net income−$18.6M
Free cash flow−$25.7M
Quarterly, 8 quarters to 30 June 2026 · latest quarter's figure shown
Total return, dividends reinvested
1W
−9.8%
1M
0.0%
YTD
−7.2%
1Y
+7.9%
From 52W high
−23.0%
From 52W low
+12.0%
$8
$12
52-week range, adjusted closes · the dot is the last close
Ticker Nerd rank

PRTA stock analysis: one number for the whole business

Consensus tells you what everyone already believes. The model scores Prothena Corp. Plc on its factor families — the same systematic rank behind the Ticker Nerd portfolio.

Where the model ranks itAs at 14 Sept 2026
98 / 100

Percentile across ~4,600 US stocks on Ticker Nerd’s systematic factor model. Higher is better. How the model is built and tested

Growth
100
Volatility
93
Issuance
92
Value
87
Revisions
77
Quality
71
Momentum
57
Size
54
Accruals
44

Growth (100): Sales and profits are climbing, and climbing faster than before.

Accruals (44): A large share of reported profit has not shown up as cash, or the balance sheet is expanding quickly — both tend to unwind.

Built and run by Aslam Ghouse, an ex-Goldman Sachs quant trader with fourteen years in markets.

Wall Street

PRTA stock forecast 2026-2027: analyst price targets & predictions

The bullish and bearish analyst opinions on PRTA, reported as data — targets and ratings, the market's view beside the model's.

Share price and the analyst range, 12 monthsAdjusted close, US dollars
$5$10$15$20$25$30$35$40Oct 25Jan 26Apr 26Jul 26PRTAHigh $36Median $20Low $8

Price targets and ratings are third-party analyst estimates, reported here as data. They are not Ticker Nerd forecasts, and they are frequently wrong.

Data provided by Twelve Data

What Wall Street says6 analysts
3 Buy2 Hold1 Sell
Low $8Median $20High $36

The green dot is the last close — the median target sits +125.7% from it.

Recent analyst actionsNewest first
DateFirmActionRatingTarget
8 May 2026CitizensMaintainsMarket Outperform$19 → $20
20 Feb 2026RBC CapitalMaintainsSector Perform—
1 Dec 2025CitizensMaintainsMarket Outperform—
7 Nov 2025HC Wainwright & Co.MaintainsBuy—
7 Nov 2025RBC CapitalMaintainsSector Perform—
28 Oct 2025Piper SandlerMaintainsOverweight—
7 Oct 2025HC Wainwright & Co.MaintainsBuy—
2 Sept 2025JMP SecuritiesMaintainsMarket Outperform—
28 Aug 2025Chardan CapitalMaintainsBuy—
28 Aug 2025Piper SandlerMaintainsOverweight—
5 Aug 2025Chardan CapitalMaintainsBuy—
5 Aug 2025HC Wainwright & Co.ReiteratesBuy—
5 Aug 2025RBC CapitalMaintainsSector Perform—
20 June 2025Cantor FitzgeraldReiteratesNeutral—
28 May 2025B of A SecuritiesDowngradeUnderperform—
27 May 2025Chardan CapitalMaintainsBuy—
27 May 2025HC Wainwright & Co.MaintainsBuy—
27 May 2025JMP SecuritiesMaintainsMarket Outperform—
27 May 2025OppenheimerDowngradePerform—
27 May 2025Piper SandlerMaintainsOverweight—

Price targets and ratings are third-party analyst estimates, reported here as data. They are not Ticker Nerd forecasts, and they are frequently wrong.

Market Radar

This page is one stock. Monday covers all of them.

Computed off the Friday close and sent before the US open.

Market Radar reports the week’s largest rank changes across roughly 4,600 US stocks, the factor behind each one, and where the market went. PRTA appears on the weeks it earns a place.

Free, every Monday. Unsubscribe any time.

Performance

PRTA vs the S&P 500

Both lines are total return — dividends reinvested — so the comparison is honest on both sides.

Over the twelve months to 14 Sept 2026, Prothena Corp. Plc returned +7.9% against +17.0% for the S&P 500, dividends included.

PRTA vs S&P 500, last 12 monthsTotal return, rebased to 100
90100110120130140Oct 25Jan 26Apr 26Jul 26PRTAS&P 500

Download this chart as an image — free to reuse; link this page as the source.

Data provided by Twelve Data

Estimates

PRTA analyst estimate revisions

Not the forecast itself — the direction analysts are revising it. Revision direction is one of the model's factor families.

Which way the estimates are movingNext fiscal year
EPS revision, 90 days
+23.4%
Analysts raising
2
Analysts cutting
0
Fundamentals

Prothena Corp. Plc (PRTA) financial data

A margin means little on its own. Each bar marks where the figure sits across the whole US universe we score.

Valuation
Trailing P/E
−2.0×

Cheaper than 85% of US stocks

Price / sales
8.3×

Cheaper than 16% of US stocks

Price / book
1.6×

Cheaper than 53% of US stocks

EV / EBITDA
−2.9×

Cheaper than 75% of US stocks

Growth & margins
Revenue growth (YoY)
−77.1%

Higher than 3% of US stocks

Earnings growth (YoY)
−77.1%

Higher than 5% of US stocks

Gross margin
—
Operating margin
−1850.2%

Higher than 4% of US stocks

Net margin
−80.7%

Higher than 7% of US stocks

Returns & dividend
Return on equity
−14.4%

Higher than 34% of US stocks

Return on assets
−10.7%

Higher than 26% of US stocks

Dividend yield
2.3%

Higher than 50% of US dividend payers

Bars mark the percentile across the ~4,600 US stocks Ticker Nerd covers, among those reporting the figure.

Key statistics

Prothena Corp. Plc (PRTA) statistics: revenue, profit & scale

The headline figures, each with its date. Every row carries its own link — cite it straight from here.

  • Prothena Corp. Plc has a market value of $454.8M and an enterprise value of $173.6M.

  • Revenue in the twelve months to 30 June 2026: $54.5M. The latest quarter shrank 77.1% year on year.

  • Net income over the same four quarters: −$44.0M, a −80.7% net margin.

  • Diluted earnings per share, trailing twelve months: $−0.84.

  • Free cash flow in the twelve months to 30 June 2026: −$60.7M.

  • Prothena Corp. Plc spent $22.5M on share buybacks in the twelve months to 30 June 2026.

  • Shares outstanding: 51.7M.

  • Trailing P/E: −2.0×; forward P/E: −5.8× — the forward figure prices analyst consensus estimates, not reported earnings.

  • Forward dividend yield: 2.26%, paying out 0% of earnings.

  • Prothena Corp. Plc employs 67 people — $814K of revenue per employee.

Statement figures: company filings via Twelve Data, four quarters to 30 June 2026 · market figures as at 15 Sept 2026

Data provided by Twelve Data

Peers

PRTA vs competitors

The nearest names by industry and size, scored by the same model — like for like.

Its peer group, ranked by the same modelBiotechnology
CompanyMarket capTKN rank
PRTAProthena Corp. Plc$454.8M
98
CABACabaletta Bio, Inc.$474.5M
29
VOGXVogenx, Inc.$481.6M
1
IRDOpus Genetics, Inc.$485.9M
53
ENTXEntera Bio Ltd.$488.3M
49
RLMDRelmada Therapeutics, Inc.$465.7M
69
PBYIPuma Biotechnology, Inc.$465.1M
92

Look up any of the roughly 4,600 stocks we score.

The rank is the raw material. Whether the rules would actually own Prothena Corp. Plc — and when they’d sell — is the membership. See the Ticker Nerd 20 →

News

Latest PRTA news & analysis

Prothena to Participate in the H.C. Wainwright 28th Annual Global Investment Conference

Business Wire · 9 Sept 2026neutral

Prothena Corporation plc announced it will participate in the H.C. Wainwright 28th Annual Global Investment Conference. The company made the announcement via Business Wire from its Dublin, Ireland headquarters.

Why it matters — A PRTA watcher would care because conference participation gives the company a public platform to present its business to investors and industry participants.

KMDA or PRTA: Which Is the Better Value Stock Right Now?

Zacks Investment Research · 14 Aug 2026neutral

Zacks Investment Research published a comparison piece examining Kamada (KMDA) and Prothena (PRTA) as potential value-stock candidates in the Medical - Biomedical and Genetics sector, posing the question of which is the better option for investors seeking undervalued stocks.

Why it matters — Prothena watchers would care because the item directly evaluates PRTA's valuation versus a peer in the same sector, highlighting how the company is being assessed in a value-investing context.

PRTA's Q2 Loss Narrower Than Expected, Pipeline Progress in Focus

Zacks Investment Research · 7 Aug 2026positive

Prothena reported a narrower-than-expected adjusted second-quarter loss, reaffirmed its 2026 cash-use guidance, and highlighted progress across partner programs as a key milestone decision approaches.

Why it matters — PRTA watchers would care because the better-than-expected result, reaffirmed guidance, and advancing partner pipeline point toward an upcoming milestone decision for the company.

Prothena (PRTA) Reports Q2 Loss, Misses Revenue Estimates

Zacks Investment Research · 7 Aug 2026neutral

Prothena reported a second-quarter net loss of $0.32 per share, narrower than the Zacks Consensus Estimate of a $0.39 loss and improved from the $1.86 per-share loss a year earlier. The company also missed revenue expectations for the quarter.

Why it matters — The better-than-expected quarterly loss provides PRTA watchers with a current measure of the company's financial performance and trajectory versus analysts' forecasts.

Prothena Reports Second Quarter 2026 Financial Results and Business Highlights

Business Wire · 6 Aug 2026neutral

Prothena reported its financial results for the second quarter and first six months of 2026 and provided business highlights in a company announcement.

Why it matters — PRTA watchers would track this report for an update on the company's financial performance and recent business developments.

FAQ

Frequently asked questions about PRTA stock

What is the PRTA stock price forecast for 2026-2027?

The 6 Wall Street analysts covering Prothena Corp. Plc have a median 12-month price target of $20, with estimates ranging from $8 to $36. These are third-party analyst estimates, not Ticker Nerd forecasts, and they are frequently wrong.

Is PRTA stock a buy right now?

Of the 6 analysts covering Prothena Corp. Plc, 3 rate it a Buy, 2 a Hold and 1 a Sell. Ticker Nerd's systematic factor model ranks Prothena Corp. Plc 98 out of 100 across roughly 4,600 US stocks as at 14 Sept 2026. None of this is personal advice — it does not consider your circumstances.

How does Ticker Nerd's model rank PRTA?

As at 14 Sept 2026, Prothena Corp. Plc ranks 98 out of 100 on Ticker Nerd's systematic factor model — a percentile across roughly 4,600 US stocks, built from its factor families. Its strongest factor family is Growth (100 of 100).

Will PRTA stock go up?

No one can know that. What the data says: the median 12-month target from 6 analysts implies +125.7% from the last close, and Ticker Nerd's factor model ranks Prothena Corp. Plc 98 out of 100 as at 14 Sept 2026. Analyst targets are third-party estimates and frequently wrong; none of this is personal advice.

What is the PRTA stock forecast for 2030?

No analyst covering Prothena Corp. Plc publishes a 2030 price target — Wall Street targets run 12 to 18 months out. Sites quoting a 2030 price for PRTA are extrapolating price history, which says nothing about the business. The furthest attributed numbers are the current analyst targets: $8 to $36 over the next 12 months.

How has PRTA stock performed over the past year?

Prothena Corp. Plc returned +7.9% over the 12 months to 14 Sept 2026, with dividends reinvested. Past performance does not indicate future returns.

What does Prothena Corp. Plc do?

Prothena Corp PLC is a clinical-stage biotechnology company focused on discovering and developing therapies for diseases linked to protein dysregulation. The company’s current work centers on investigational treatments for neurodegenerative disorders and rare peripheral amyloid diseases, areas where misfolded proteins play a critical role in disease progression.

What is the latest news on PRTA?

The most recent item we track (Business Wire, 9 Sept 2026): "Prothena to Participate in the H.C. Wainwright 28th Annual Global Investment Conference". Prothena Corporation plc announced it will participate in the H.C. Wainwright 28th Annual Global Investment Conference. The company made the announcement via Business Wire from its Dublin, Ireland headquarters.

Company

About Prothena Corp. Plc.

Prothena Corp PLC is a clinical-stage biotechnology company focused on discovering and developing therapies for diseases linked to protein dysregulation. The company’s current work centers on investigational treatments for neurodegenerative disorders and rare peripheral amyloid diseases, areas where misfolded proteins play a critical role in disease progression. Its pipeline includes both wholly owned and partnered programs aimed at conditions such as Alzheimer’s disease, Parkinson’s disease, AL amyloidosis, and ATTR amyloidosis. Prothena Corp PLC also applies its proprietary scientific platform to investigate targeted biologic therapies designed to address complex disease pathways in the brain and peripheral tissues. Headquartered in Dublin, Ireland, Prothena Corp PLC plays a specialized role in the biotechnology market by advancing experimental medicines for serious disorders with limited treatment options.

CEO Dr. Gene G. Kinney Ph.D. · 67 employees · Ireland · https://www.prothena.com