Watch

PRTAProthena Corporation plc

Healthcare · Biotechnology · small-cap ($448M)
-23.1%
from rolling 252-day high of $11.80 set 2026-05-08 · 97d ago
Current
$9.08
Decline depth
-23.1%
Decline σ
1.7σ
TFC
2/5 bearish
Rolling 252-day high Up day Down day Last 90 trading days · data from Alpaca

Since tracking began

$PRTA has been tracked since 2026-03-01. It was down 41.8% from its 52-week high then — now down -23.1%.

That's 3.4 percentage points deeper than the day it joined. It bottomed 51.1% below that high along the way.

Decline from the 52-week high as it stood on 2026-03-02 (fixed anchor) → today. Split-adjusted, Alpaca. Observed history, not a forecast.

Structural break signals

PRTA qualifies for the Watch on decline depth.

Decline depth
-23.1%
From rolling 252-day high of $11.80, 97d ago. Past the 20% Watch threshold.
Time-frame continuity
2/5 bearish
Latest bar across daily/weekly/monthly/quarterly/yearly time frames. A bar counts as bearish when it's a 2-Down or a red 3.
Decline sigma
1.7σ
Drop from local high over the last 5 bars, expressed in units of the stock's typical daily volatility (2.04% per day).

The structural read

What price action says about PRTA.

PRTA qualifies for the Watch on decline depth — down -23.1% from its rolling 252-day high.

Earnings on file: 2026-05-07. Tiering is unaffected by earnings dates — listings reflect price structure only.

Questions about PRTA

What people ask.

Why is PRTA on Broken Stocks?

PRTA qualifies for the Watch on decline depth. It is down -23.1% from its rolling 252-day high of $11.80, set on 2026-05-08 — 97d ago.

Is PRTA a falling knife?

No. The falling-knife label usually implies a steep, severe drop — typically 30% or more from a fresh high. PRTA is down -23.1% from its 52-week high, which qualifies for the Watch tier but is shallower than the falling-knife pattern. It's an early-stage decline rather than a sharp breakdown.

Is PRTA a buy?

Broken Stocks does not issue buy or sell recommendations. The list is a rules-based technical warning system. It tracks structural decline depth and recency — not company quality, management, fundamentals, or news. Always do your own research and consult a licensed advisor.

Where is PRTA trading inside its 52-week range?

At $9.08, PRTA sits 47.6% of the way from its 52-week low ($6.61) to its 52-week high ($11.80). A reading below 25% indicates price is hugging the bottom of the range; above 75%, the top.

How fast has PRTA been declining?

The current 23.1% decline accrued over 97d, which annualizes to roughly -86.9% per year. Annualized pace is a sanity check — a 30% decline in three months is a different signal than a 30% decline over two years.

How does PRTA compare to its sector?

There are 140 other Healthcare tickers on Broken Stocks: 68 Red, 34 Amber, 38 Watch, with 48 showing recovering structural signals. Median sector decline is -36.1% — PRTA's decline is shallower than the sector median.

Does PRTA's earnings date affect its tier?

No. Tiering is decided purely by decline depth and recency of the rolling-high date. The earnings date on file (2026-05-07) is shown for reference only — listings can move tier between scans based on closing prices, regardless of fundamentals or news events.