A property derivative is a financial derivative whose value is derived from the value of an underlying real estate asset. In practice, because individual real estate assets fall victim to market inefficiencies and are hard to accurately price, property derivative contracts are typically written based on a real estate property index. In turn, the real estate property index attempts to aggregate real estate market information to provide a more accurate representation of underlying real estate asset performance. Trading or taking positions in property derivatives is also known as synthetic real estate.