on the sidelines

Investors who refrain from investing because of market uncertainty are said to be on the sidelines. The analogy is to a football game, in which spectators on the sidelines do not actively participate in the game. Investors on the sidelines normally keep their money in short-term instruments such as money market mutual funds, which can be tapped instantly if the investor sees a good opportunity to reenter the stock or bond markets. Market commentators frequently say that trading activity was light "because investors stayed on the sidelines."

Observing rather than taking part, out of the action, as in Bolivia's neighbors remained on the sidelines, waiting to see which faction in the dispute would prevail. This idiom comes from sports. The sidelines are the two lines defining the sides of the court or playing field and the area immediately beyond them where, in such sports as football, the non-playing team members sit. [First half of 1900s]