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

Last close, 14 Aug 2026
$8.86
−2.42% 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 15 Aug 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
Total return, dividends reinvested
1W
+1.1%
1M
+2.5%
YTD
−7.2%
1Y
+9.9%
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 15 Aug 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
Issuance
92
Volatility
90
Value
87
Revisions
79
Quality
72
Size
55
Momentum
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.

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.

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
−1200.0%
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 17% of US stocks

Price / book
1.6×

Cheaper than 54% of US stocks

EV / EBITDA
−3.1×

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 51% of US dividend payers

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

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
OABIOmniAb, Inc.$486.6M
93
KYTXKyverna Therapeutics, Inc.$493.8M
41
LRMRLarimar Therapeutics, Inc.$460.4M
35
BLSMBlossomhill Therapeutics, Inc.$495.8M
0
OCGNOcugen, Inc.$457.0M
24
ENTXEntera Bio Ltd.$500.4M
46

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

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.

Prothena to Report Second Quarter 2026 Financial Results on August 6

Business Wire · 30 July 2026neutral

Prothena announced it will release its second quarter and first six months of 2026 financial results on August 6, 2026.

Why it matters — This date gives PRTA watchers a scheduled milestone for the company's next financial update and potential commentary on its pipeline progress.

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 15 Aug 2026. None of this is personal advice — it does not consider your circumstances.

How does Ticker Nerd's model rank PRTA?

As at 15 Aug 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 15 Aug 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 +9.9% over the 12 months to 14 Aug 2026, with dividends reinvested. Past performance does not indicate future returns.

What does Prothena Corp. Plc do?

Prothena Corporation plc is a late-stage clinical biotechnology company focused on the discovery and development of novel therapies targeting protein dysregulation, particularly in neurodegenerative diseases and rare peripheral amyloid diseases. The company leverages deep expertise in the biology of misfolded proteins to advance investigational antibody therapies and innovative platforms like CYTOPE.

What is the latest news on PRTA?

The most recent item we track (Zacks Investment Research, 14 Aug 2026): "KMDA or PRTA: Which Is the Better Value Stock Right Now?". 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.

Company

About Prothena Corp. Plc.

Prothena Corporation plc is a late-stage clinical biotechnology company focused on the discovery and development of novel therapies targeting protein dysregulation, particularly in neurodegenerative diseases and rare peripheral amyloid diseases. The company leverages deep expertise in the biology of misfolded proteins to advance investigational antibody therapies and innovative platforms like CYTOPE. Its pipeline features key programs such as prasinezumab, a humanized monoclonal antibody in phase 3 trials for Parkinson's disease and synucleinopathies through collaboration with Roche; coramitug in phase 3 for transthyretin amyloidosis with cardiomyopathy via partnership with Novo Nordisk; and BMS-986446 in phase 2 for Alzheimer's disease with Bristol Myers Squibb. Additional wholly-owned candidates include PRX012 and PRX019 in early clinical stages for Alzheimer's and other neurodegenerative conditions, alongside preclinical efforts like the dual Aβ-tau vaccine PRX123. Prothena Corporation plc maintains strategic collaborations that support its mission to deliver transformative treatments for devastating diseases affecting millions worldwide. Incorporated in 2012 and headquartered in Dublin, Ireland, it operates at the forefront of neuroscience innovation in the healthcare sector.

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