Even if consumption is excludable, market provision of a public good is likely to be inefficient. Suppose now that the fireworks display is excludable: people cannot see the show without purchasing an admission ticket to a coliseum. A profit-maximizing entrepreneur sells tickets. Recall from Chapter 4 that Pareto efficiency requires that price equal marginal cost. Because a public good is nonrival in consumption, by definition the marginal cost of providing it to another person is zero. Hence, efficiency requires a price of zero.