The all-time high is the highest price any given asset has ever reached on the open market.
An asset reaching a new ATH can provide both opportunities and pitfalls for traders. If the asset is reaching a new ATH on a regular basis, traders can recognize the upward trend, and invest accordingly. However, a strong technical and fundamental analysis is also necessary in order to determine when the asset price will hit its resistance and begin to drop again. An all-time high should not, in and of itself be used to develop a trading strategy, but it can – and should be – one of several tools taken into account.