指当股市暴涨时，为避免股价升至更高以比预期高的价格买进股票，抑或指当股市暴跌，为避免股价跌至更低以比预期低的价格卖出股票。

Entering or exiting of a trend after the trend has already been well established. Investors are often unaware of the fact that they are chasing the market, which can dent the value of a portfolio. This type of investing is often seen as irrational as decisions are often based on emotion instead of careful analysis of the value of the investment.

Chasing the market refers to both the entering into highly priced positions after they have rapidly increased and become overvalued as well as the exiting of positions after they have rapidly decreased and become undervalued. During the internet bubble some investors entered the rapidly appreciating sector well after the trend had been established and lost considerable sums when the bubble bust.