Fibonacci Retracement
Also called: fib levels, fibonacci levels, golden ratio trading
Fibonacci retracement marks levels at 23.6%, 38.2%, 50% and 61.8% of a prior move as candidate turning points for a pullback. There's no accepted mechanism connecting a medieval number sequence to markets, and 50% isn't even a Fibonacci ratio. It persists because so many traders watch the same levels that orders genuinely cluster there — self-fulfilling rather than predictive.