Business cycle (also called economic cycle or trade cycle) is the circular movement of an economy as it moves from expansion to contraction and back again. Economic cycles have a big impact on investment performance. U.S. economic cycles last about five and a half years on average, ranging from just 18 months during the peak-to-peak cycle in 1981-1982 up to the current record-long expansion that began in 2009. The exact causes of a cycle and what factors contribute to the length are highly debated. The economic cycle has four stages: expansion, boom, contraction, and slump.