Bull markets do not die of old age, according to market history, undercutting a widespread worry on Wall Street that the current rally has simply grown too long to continue. The concern has spread as the current bull run stretches on, with investors asking whether the advance has entered its final innings. Historical data says that framing misses the point: expansions end because of specific economic shocks, not because a calendar hits some limit.
What actually kills a bull market, according to market strategists who have studied past cycles, is a recession, a policy error by the Federal Reserve, or an exogenous shock severe enough to break corporate earnings. The length of a rally on its own has never been the trigger. That distinction matters right now because it shifts the question from "how old is this bull market?" to "what could actually end it?"
Long expansions have a track record of running far longer than skeptics expect. The bull market that began in March 2009 and ran until early 2020 lasted nearly 11 years, the longest on record, and it did not expire from exhaustion. It ended when the COVID-19 pandemic shut down the global economy in a matter of weeks, a shock no calendar-based model would have predicted.
The 1990s bull market offers another case. It ran from 1990 to 2000, powered by the dot-com boom, and only reversed when the technology bubble burst and a wave of internet companies collapsed. Again, the cause was specific: an asset bubble and the recession that followed, not the passage of time.
For investors, the practical implication is that watching the calendar is less useful than watching the fundamentals. Corporate earnings growth, the trajectory of interest rates, credit conditions, and signs of stress in the labor market are the variables that have historically preceded market tops. A rally that is old but still supported by those fundamentals is not, by itself, in danger.
The current worry has surfaced repeatedly during this cycle, with each new record high bringing fresh predictions that the run must be nearing its end. Those predictions have been wrong so far. The bull market has continued to climb even as the list of things that could end it has stayed short.
None of this guarantees the current rally will last. It only means that age alone is not the signal investors should be watching. The forces that end bull markets are identifiable in real time, and they look nothing like a birthday.
