Well, it is, and investments can lose money. The fact that real estate is commonly leveraged (i.e. people buy with borrowed money, often around 80% of the price) means that small fluctuations in price can cause big changes in how much equity you have. For example, if you buy a $100,000 house with an $80,000 loan, and the price goes up 20%, you have doubled your equity. But if the price drops 20%, your equity is wiped out. (This is not including the effect of transaction costs, which are significant for real estate transactions.)