STE·STERIS plc

Realized volatility (21d)

14.4% 19th pct

Below its peak

-18.3%

vs 200-day average

-3.2%

Up days (1y)

48%

STERIS plc is currently running 14.4% annualised volatility over the last 21 sessions. Measured against STE's own 13 years of daily returns rather than a market-wide average, that is the 19th percentile — unusually subdued by its own history, against a typical reading of 20.8%. The distinction matters because a number that looks calm for one stock is turbulent for another, and the absolute figure on its own tells you neither.

STE is trading -18.3% below its running peak. Across 12 full years on file, its median worst-drawdown-in-a-year was -15.4%, and the deepest was -36.5% in 2022. The current drawdown is already deeper than this stock's typical annual low point, which puts it in the part of its range where past recoveries began — and where past declines also continued.

Price sits -3.2% from its 200-day moving average. Against every other day in its history, that gap ranks at the 16th percentile — a narrower gap than it typically runs. Over the past year STE closed higher on 48% of sessions, and it is currently 1 session into a rising streak.

On October specifically: over 14 years of records, STE finished the month higher 9 of 14 times, with a median return of +1.1% and an average of +2.4%. Its strongest month historically has been May at +4.3% on average, its weakest September at -1.8%. Seasonality is a weak signal on its own — a decade is a small sample and regimes change — but it is a real distribution rather than a rule of thumb.

Overnight risk is measurable too: STE has opened more than 2% away from the prior close in 67 of 3,268 sessions (2.1% of the time), with the largest gaps running +6.1% and -8.6%. For anyone holding through an event, that rate is a better guide to overnight exposure than the intraday range.

Across the last 3 dated reports on file, STE moved an average of 1.8% in the session after earnings, closing higher 3 of those 3 times, with a median move of +0.8% and a largest of +4.4%.

All figures computed from 3,269 daily closes between 2013-10-15 and 2026-10-14, split-adjusted, recomputed daily. Percentiles are against STE's own 13-year history, not a peer group or index.