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PRTA · Prothena Corp Public Ltd Co

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$9.61 +0.26 (+2.78%) At close · Sep 1
Market Cap
$478.97M
Shares
51.34M

Price & Indicators

20d MA 50d MA 200d MA Earnings Filing Insider Congress Investor day
Close$9.61 Open$9.28 Day$9.26–9.63 52W close$7.91–11.51 Avg vol 30d444K Short int8.5M · 16.6% float · 19.6d Short vol74% Last earningsFeb 19, 2026 DataJan 2020–Sep 2026 Filing10-Q · Aug 6

Up next

Next earnings call
Feb 22, 2027 Est · unconfirmed · in 25 wks
FQ3-26 quarter ends
~Sep 30, 2026 Est
filed Aug 6, 2026

Equibles Rating

blended score · not investment advice
Overall
Neutral
SellHoldBuy
Technical Buy Momentum Neutral Sentiment Neutral Fundamentals Weak Quant / Vol Very High
Market backdrop VIX 16.3 · calm Equity put/call 0.67
Technical
price trend
Buy
50 / 200-day cross No cross
Price vs 200-day avg +1%
above
Price vs 50-day avg +6%
above
RSI (14) 61
neutral
MACD trend Positive
52-week position 47%
mid-range
Volume (OBV) Confirms
volume backs price
Momentum
relative strength
Neutral
1-month return +13%
trailing
6-month return 0%
trailing
YTD return +1%
this year
Relative strength −12%
vs S&P · 6-mo
Sentiment
smart money
Neutral
Trend (MA cross) No cross
50d $9 › 200d $9 — 200d above 50d
Institutional flow Accumulating
+3% holders QoQ · +29 funds added
Insider flow Accumulating
Net +$2.4M over 90 days · 0% sells
Short interest Rising
16.65% of float · ▲ +4.6% MoM · 19.6 days cover
Volume signal Normal
Volume near normal
Institution breadth Steady
191 holders — mid 3-yr range
Squeeze score 82
high risk · 0–100
Fundamentals
Weak
Revenue growth −15%
Y/Y
EPS growth −100%
Y/Y
Buyback $100.0M
authorized
Quant / Vol
risk profile
Very High
Volatility 48%
annualized · 1-yr
Max drawdown −31%
past year
ATR 4.3%
of price · 14-day

Blended from price, momentum, positioning, fundamentals & volatility · daily-close · not investment advice. Market backdrop is context, not part of the score.

Technicals

trend & momentum for long-term holders Buy
0 · 4 · 3
50 / 200-day cross
No cross Neutral
Price vs 200-day avg
+1% Bullish
Price vs 50-day avg
+6% Bullish
RSI (14)
61 Neutral
MACD trend
Positive Bullish
52-week position
47% Neutral
Volume (OBV)
Confirms Neutral
Market signals — smart money & positioning
Bullish · 2 of 6
Trend (MA cross) No cross
50d $9 › 200d $9 — 200d above 50d
Institutional flow Accumulating
+3% holders QoQ · +29 funds added
Insider flow Accumulating
Net +$2.4M over 90 days · 0% sells
Short interest Rising
16.65% of float · ▲ +4.6% MoM · 19.6 days cover
Volume signal Normal
Volume near normal
Institution breadth Steady
191 holders — mid 3-yr range
Price context
position in its 52-week range
Range low $8 Now $10 · 47% Range high $12
vs 200-day avg +1% vs 50-day avg +6%

Illustrative technical + ownership context — a signal mix, not investment advice.

Versus peers

Biotechnology — same industry group
Open screener →
Company Mkt cap YTD Rev growth Y/Y P/E Short % shares
PRTA
Prothena Corp Public Ltd Co
this stock
$478.97M +0.6% -14.8% 16.6%
VRTX
Vertex Pharmaceuticals Inc / Ma
$137.30B +20.8% +46.2% 31.6 1.6%
REGN
Regeneron Pharmaceuticals, Inc.
$81.77B +6.7% +20.8% 19.7 2.3%
ARGX
Argenx SE
$64.16B +22.3% 1.9%
CSLLY
Csl Ltd
$59.51B 0.0%

Peers by industry group · P/E from as-reported trailing EPS · short % is of shares outstanding

At a glance

key data from every section
Ownership
Institutional Holders Accumulating
Holders
191
% held
94.1%
Net QoQ
+829.9K sh
Top holder
FMR LLC
Held Float
View
Held by Funds
Fund positions
60
View
Short & Settlement
Short Interest Rising
Shares short
8.5M
Days to cover
19.6d
Change
+372.7K sh
View
Short Volume
Short vol %
74%
As of
Sep 1, 2026
Short Total
View
Fails to Deliver
FTD shares
368
Value
$3.1K
As of
Aug 6, 2026
View
Off-Exchange
Off-exchange %
31.0%
Week of
Jul 27, 2026
Off-exch Lit
View
Smart Money
Insider Trades Net buying
Net (90d)
+$2.4M
Buyers / Sellers
1 / 0
Buyers Sellers
View
Financials
Financials
Revenue (FY)
$9.7M
Net income (FY)
$-244.1M
EPS diluted
$-4.53
View
Buybacks
Authorized
$100.0M
View
Filings
SEC Filings
Latest
8-K
Filed
Aug 6, 2026
This year
10
View
Proposed Sales
Value
$64.9K
Shares
7.7K
Filed
Jul 29, 2026
View
Earnings & Events
Earnings Calls
Last call
Feb 19, 2026
View
Investor Relations
Latest news
Prothena Reports Second Quarter 2…
Published
Aug 6, 2026
View

Performance

5D 20D 120D MTD YTD
PRTA +2.0% +13.2% +0.3% +2.8% +0.6%
SPY -0.5% -1.2% +12.6% -0.7% +11.7%
vs SPY +2.6% +14.4% -12.3% +3.5% -11.1%

Capital returns

Buyback program · as of Feb 27, 2026
Authorized
$100.00M
Spent (derived)
Remaining

Dividends per share over the trailing 365 days by ex-date · buyback figures as last reported in SEC filings ("spent" derived as authorized − remaining; when several programs run concurrently, authorized is their combined total per the newest filing) · components shown separately — trailing-year buyback spend isn't tracked, so no combined shareholder yield is derived.

Key facts CIK 1559053 CUSIP G72800108 13F (30d) 156 filings 153 filers Visit website Investor relations