How Long Will This Bull Run Last.. Insights from 100 yrs of history! By 1M65 • August 11, 2026How Long Do Bull Runs Last? The Data Might Surprise You We studied every S&P 500 bull run since 1927 and every Nasdaq 100 bull run since 1985 — 99 years and 41 years of daily price data — to find out how long bull runs actually last, how far they run, and what causes them to end. Tonight we break down the numbers: median duration, median gains, the corrections that happen inside every bull run, and the four types of bull run that repeat throughout history.