DEFINITION of 'Reaction'
A reversal in the movement of a security's price. Reaction is most often associated with a downward movement in the price of a security after a period of upward movement, as investors sell off shares or decrease the volume of buy orders for fear of the security being overvalued. Reactions are likely to be mild and lead to a slight increase or decrease in price, rather than a large change in value. A reaction is similar to a correction but lacks the same intensity.
BREAKING DOWN 'Reaction'
Reactions are generally considered to be positive for the overall health of the market, since unending price increases can cause inflation or result in an even larger price drop if a company doesn't meet expectations. A reaction is likely to prevent events such as runs or high volume sell offs at later dates.