The term gray market refers to unauthorized or unofficial markets for goods. Unlike black market goods, there is no implication that gray market goods violate any laws, but their distribution through a gray market rather than official or expected channels may be unintended by the manufacturer. Gray markets in drugs may exist for several reasons, including a shortage of particular drugs obtainable through official channels, and lower prices on drugs obtained through the gray market rather than official channels. Gray market drugs are a concern for several reasons, including lack of oversight and quality assurance, and insufficient or inconsistent supply.