The term MegaCorp (sometimes called Zaibatsu) refers to a corporation that is a massive conglomerate (usually private), holding monopolistic or near-monopolistic control over multiple markets (thus exhibiting both a horizontal and a vertical monopoly). Megacorps are so powerful that they are above the government laws, possess their own heavily armed (often military-sized) private armies, be the operator of a privatized police force, hold "sovereign" territory, and even act as outright governments. They often exercise a large degree of control over their employees, taking the idea of "corporate culture" to an extreme. Previously a staple of fiction, in the early 21st Century they began to emerge as reality.