An economic theory created by Soviet economist Nikolai Kondratiev that states that Western capitalist economies are susceptible to high performance volatility.

Also known as "Kondratiev cycle".

Kondratiev called these large performance fluctuations "super-cycles," which last 50-60 years. Kondratiev claimed to have predicted in the 1920s the stock market crash of 1929, also known as Black Thursday. His prediction was based on the market crash of 1870.