A fire sale is the sale of goods at extremely discounted prices. The term originated in reference to the sale of goods at a heavy discount due to fire damage. It may or may not be defined as a closeout, the final sale of goods to zero inventory. They are said to occur in the financial markets when bidders who value assets highly are prevented from bidding on them, depressing the average selling price below what it otherwise would be. This lowering of the price can cause even further issues because it may be inaccurately perceived as signalling negative information.

The term is adapted from reference to the sale of fire-damaged goods at reduced prices. In Proceedings of the Fitchburg [Mass.] Historical Society and Papers Relating to the History of the Town Read by Some of the Members the following entry is found:

In December, 1856, the account of an extensive fire in the American House mentions the following occupants: E. B. Gee, clothing; T. B. Choate, drugs; J. C. Tenney, boots and shoes; Maraton Upton, dry goods; and M. W. Hayward, groceries. Maraton Upton removed his stock to No. 9 Rollstone block, and advertised "Extraordinary fire sale; customers are invited to call and examine goods which are still warm."

The term also has a counterpart in "railroad salvage", the discount sale of goods damaged in derailment or other accidents.

According to Plutarch, Crassus would show up to a burning building with a fire brigade and offer to put out the fire, or sometimes to buy the property at an outrageous discount. If the owner agreed, he would put out the fire. If they refused, he would stand by and let it burn.

In professional sports, a fire sale occurs when a team trades many of its veteran players, especially expensive star players, to other teams for less expensive and usually younger players. Teams usually have a fire sale for financial reasons. The term is generally thought of as different from merely "rebuilding" a team, because during a rebuilding process, teams often obtain players who are already in the major leagues or who are close to being major-league-ready, while retaining at least some of their key veterans (such as a franchise player) while also getting players from their minor league system; most rebuilding teams have few veterans remaining to jettison in the first place. On the other hand, trades in a fire sale often bring a team draft picks and prospects who have little to no major-league experience in their sport, in exchange for proven, experienced veterans. The term comes from the perception that the team is trying to get rid of all its players.

In sports, the term fire sale is especially used in Major League Baseball, where the most infamous fire sale occurred in 1997. Weeks after winning the 1997 World Series, the Florida Marlins began trading away several of their high salary players and key cogs in the championship run, with Moisés Alou and Al Leiter among the first of many to go throughout the off-season and well into the 1998 season. This ended any realistic chance of the Marlins' defending their title. They plummeted to a 54–108 record in 1998, the worst ever by a defending World Series champion.

Owner and manager Connie Mack put the Philadelphia Athletics through a fire sale twice. In 1914, the Athletics lost the 1914 World Series to the "Miracle Braves" in a four-game sweep. Mack traded, sold or released most of the team's star players soon after, in what could be considered as the first fire sale in organized sports.^{[citation needed]}