Rules (fixed before looking at results, applied to each stock's price relative to the S&P 500 so market-wide rallies do not count):

• Base: the 52 weeks before the knee trend at most +10% a year (last 6 months at most +15% a year), and the base's high is at most 2× its low.
• Rise: the price reaches 2× the base level within 1 to 12 months of the knee.
• Sustain: for the next 26 weeks the median stays at or above 2× and never falls below 1.6×.
• Liquidity: base price at least $3 and median daily trading at least $1M.

The knee is placed by fitting a two-segment line to weekly log prices; every rule is checked against the year right before that knee. Scan of ~12,000 US stocks with FMP prices, 2016 to September 2026.

Every match, grouped by the mechanism of the move

Causes, first public signals and lead times were researched after the fact with web search (sources in the data table); they describe what happened, not a tested strategy. Within each group, earliest knee first. Each chart shows 6 months before its base year to 9 months after it first reached 2× (use the range control beside a title to widen it): month-end share price and price relative to the S&P 500 scaled to the price at the knee. The shaded span is the base year, the accent line the knee, the other line the month it first reached 2×. Drivers were labelled after the fact by a model and reviewed by hand; they describe what happened, not what was knowable at the knee.