In Austrian business cycle theory, malinvestments are badly allocated business investments, due to artificially low cost of credit and an unsustainable increase in money supply. Central banks are often blamed for causing malinvestments, such as the dot-com bubble, and the United States housing bubble. Austrian economists such as Nobel laureate F. A. Hayek advocate the idea that malinvestment occurs due to the combination of fractional reserve banking and artificially low interest rates misleading relative price signals which eventually necessitate a corrective contraction—a boom followed by a bust.The concept dates back to at least 1867. In 1940, Ludwig von Mises wrote, "The popularity of inflation and credit expansion, the ultimate source of the repeated attempts to render people prosperous by credit expansion, and thus the cause of the cyclical fluctuations of business, manifests itself clearly in the customary terminology. The boom is called good business, prosperity, and upswing. Its unavoidable aftermath, the readjustment of conditions to the real data of the market, is called crisis, slump, bad business, depression. People rebel against the insight that the disturbing element is to be seen in the malinvestment and the overconsumption of the boom period and that such an artificially induced boom is doomed. They are looking for the philosophers' stone to make it last."