Light SA is a Brazilian private-public utility of which the state-owned power company, CEMIG, wields a controlling stake. Headquartered in the city of Rio de Janeiro, Light primarily generates, distributes, and trades energy. To do this, the company owns and operates a portfolio of hydroelectric power plants that serve the Brazilian state of Rio de Janeiro. Light derives most of its revenue from the supplying of energy, with network usage and the construction of assets also bringing in substantial amounts of revenue. The vast majority of the company's customers are residential consumers. Larger commercial customers represent the second- largest group.