A monopsony is a market condition in which there is only one buyer, the monopsonist. Like a monopoly, a monopsony also has imperfect market conditions. The difference between a monopoly and a monopsony is primarily in the difference between the controlling entities. A single buyer dominates a monopsonized market while an individual seller controls a monopolized market. Monopsonists are common in areas where they supply most or all of the region's jobs.