In real estate, betterment is the increased value of real property from causes other than investment made by the property owner.[1] It is, therefore, usually referred to as unearned increment or windfall gain.
When, for instance, a property is rezoned for higher-value uses, or nearby public improvements raise the value of a piece of private land, a property owner is "bettered" due to the actions of others. Because of this, capturing the value of betterment for the public through taxation or other means is a common policy approach.