Tying charges arise when a company is said to have made the sale of one good dependent on the purchase of a second distinct good. The Antitrust Division of the United States Department of Justice is responsible for prosecuting this anti-competitive practice, and most states have additional laws against tying, enforced on the state level.
Horizontal tying allegations surface when a corporation is said to have compelled customers to pay for an unrelated product along with the desired one, and vertical tying accusations arise when that company is believed to have required customers to purchase related products or services.