11 .  marginal revenue is very different for monopolies. Monopolies have a decreasing marginal revenue curve. The marginal revenue a monopoly gets from selling an additional unit will always be less than the price the unit is sold for. Since a monopoly's output affects the market price (unlike a competitive firm's output), the monopolist will get revenue equal to the price from selling an additional unit; however, in order to sell an additional unit, the monopolist must decrease the price for all units sold, and this is revenue that the monopolist loses. The sum of the revenue gained from selling the additional unit and the revenue lost from lowering the price on all units is the monopoly's marginal revenue.