Question
True or False - the monopolists MC curve is their short run supply curve?
Answer: False
A monopolist’s marginal cost (MC) curve is not its short-run supply curve. For a single-price monopolist, an interior profit maximum normally satisfies MR = MC, and the selling price comes from demand at that quantity. The price is not read from MC.
A supply curve gives quantity supplied at each externally given price, holding other supply conditions fixed. A monopolist’s choice also depends on the demand curve and its associated marginal revenue. MC alone therefore cannot determine a demand-independent price–quantity relationship.
Why the competitive rule does not transfer
A price-taking firm has MR = P. Under the usual competitive assumptions, its rising MC segment above minimum average variable cost describes short-run supply. A single-price monopolist faces downward-sloping demand and generally has MR below P. Equating P with MC would select a different output.
The absence of a monopoly supply curve does not mean production is undefined. Given demand and costs, the firm can choose an optimal output, subject to shutdown and feasibility checks.
Evidence boundary
This answers the standalone true-or-false item 11 in the cited course’s mainstream monopoly section. It uses the standard single-price model and an interior optimum where applicable. It does not cover regulated pricing or perfect price discrimination, and the source supplies no numerical demand or cost data.
Sources
These references support the concepts and methods used in the explanation above.