Price war is "commercial competition characterized by the repeated cutting of prices below those of competitors". One competitor will lower its price, then others will lower their prices to match. If one of them reduces their price again, a new round of reductions starts. In the short term, price wars are good for buyers, who can take advantage of lower prices. Often they are not good for the companies involved because the lower prices reduce profit margins and can threaten their survival.

In the medium to long term, price wars can be good for the dominant firms in the industry. Typically, the smaller, more marginal firms cannot compete and must close. The remaining firms absorb the market share of those that have closed. The real losers, then, are the marginal firms and their investors. In the long term, the consumer may lose too. With fewer firms in the industry, prices tend to increase, sometimes higher than before the price war started.