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Student discounts, airline fares, and bulk pricing are the same trick: charging different buyers different prices for one good. The three degrees, explained.

Allocative efficiency means resources go to their highest-valued uses (P = MC). Productive efficiency means goods are produced at minimum cost.

The profit-maximization rule states that firms maximize profit by producing where marginal revenue equals marginal cost.

Antitrust law prevents firms from monopolizing markets, fixing prices, or merging in ways that substantially reduce competition.

Market power is the ability of a firm to profitably set price above marginal cost. It is the defining feature of monopoly and oligopoly — and the primary…

Long-run equilibrium is the state a competitive market reaches after all entry and exit adjustments are complete.

Deadweight loss is value that simply vanishes when a monopoly restricts output — trades that would benefit everyone but never happen. Here is how to see it.

It sounds like doom: competition pushes profit to zero. The reality is subtler, the math reassuring, and the takeaway reshapes how you judge any business.

Monopolies aren't born from being biggest — they're built and defended by barriers that keep rivals out. The main ways control forms, and how it's policed.

The shutdown condition tells a firm when it loses less money by halting production than by continuing.

Producer surplus is the difference between the price a seller receives and the minimum price they would have accepted.

Deadweight loss is the reduction in total economic surplus from market inefficiency — units where the benefit to buyers exceeds the cost to sellers that go…

Firms maximize profit where marginal revenue equals marginal cost. Here's what that means, why it's always true, and how to apply it step by step.

Price discrimination occurs when a seller charges different prices to different buyers for the same good based on their willingness to pay.

A natural monopoly exists when one firm can supply the entire market at lower cost than two or more competing firms.

An idealized market of countless tiny sellers, an identical product, and zero pricing power. It rarely exists in full, yet it anchors all of economics.

Losing money doesn't always mean stop. Economics splits idling temporarily from leaving for good — and the deciding number isn't the one most people watch.