A price ceiling is a government-imposed price control or limit on how high a price is charged for a product. Governments intend price ceilings to protect consumers from conditions that could make necessary commodities unattainable. However, a price ceiling can cause problems if imposed for a long period without controlled rationing. Price ceilings can produce negative results when the correct solution would have been to increase supply. Misuse occurs when a government misdiagnoses a price as too high when the real problem is that the supply is too low. In an unregulated market economy price ceilings do not exist.
Rent control is a price ceiling on rent. When soldiers returned from World War II and started families (which increased demand for apartments), but stopped receiving military pay, many could not deal with the jumping rent. The government put in price controls, so soldiers and their families could pay the rent and keep their homes. However, this increased the quantity demanded for apartments and lowered the quantity supplied, meaning that available apartments were rapidly taken until none were left for late-comers. Price ceilings create shortages when producers are allowed to abdicate market share or go unsubsidized.