Betterment

In real estate, betterment is the increased value of real property from causes other than investment made by the property owner. 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.