北京大学：《微观经济学》垄断行为

Chapter Twenty-Five Monopoly Behavior 垄断行为

Chapter Twenty-Five Monopoly Behavior 垄断行为

How Should a monopoly Price? So far a monopoly has been thought of as a firm which has to sell its product at the same price to every customer. This is uniform pricing Can price-discrimination(差别定价 earn a monopoly higher profits?

How Should a Monopoly Price? So far a monopoly has been thought of as a firm which has to sell its product at the same price to every customer. This is uniform pricing. Can price-discrimination （差别定价 ）earn a monopoly higher profits?

Structure First-degree price discrimination Second-degree price discrimination Third-degree price discrimination Bundling Two-part tariff

Structure First-degree price discrimination Second-degree price discrimination Third-degree price discrimination Bundling Two-part tariff

Types of Price Discrimination 1st-degree: Each output unit is sold at a different price. Prices may differ across buvers 2nd-degree: The price paid by a buyer can vary with the quantity demanded by the buyer. But all customers face the same price schedule. E.g. bulk-buying discounts

Types of Price Discrimination 1st-degree: Each output unit is sold at a different price. Prices may differ across buyers. 2nd-degree: The price paid by a buyer can vary with the quantity demanded by the buyer. But all customers face the same price schedule. E.g. bulk-buying discounts

Types of Price Discrimination 3rd-degree: Price paid by buyers in a given group is the same for all units purchased. But price may differ across buyer groups E.g., senior citizen and student discounts vs, no discounts for middle-aged persons

Types of Price Discrimination 3rd-degree: Price paid by buyers in a given group is the same for all units purchased. But price may differ across buyer groups. E.g., senior citizen and student discounts vs. no discounts for middle-aged persons

First-degree Price Discrimination Each output unit is sold at a different price. Price may differ across buyers. It requires that the monopolist can discover the buyer with the highest valuation of its product, the buyer with the next highest valuation and so on

First-degree Price Discrimination Each output unit is sold at a different price. Price may differ across buyers. It requires that the monopolist can discover the buyer with the highest valuation of its product, the buyer with the next highest valuation, and so on

First-degree Price Discrimination Output unit Sell the y'th unit for sp(y) p(y)H Mc(y) ply y y

First-degree Price Discrimination p(y) y $/output unit MC(y) y p(y) Sell the th unit for $ y p(y)

First-degree Price Discrimination Output unit Sell the y'th unit for sp(y). Later on p(y'A sell the y th unit for Sp(y") p(y") Mc(y) ply yy y

First-degree Price Discrimination p(y) y $/output unit MC(y) y p(y) y p(y) Sell the th unit for $ Later on sell the th unit for $ y p(y). y p(y)

First-degree Price Discrimination Output unit Sell the y'th unit for sp(y). Later on p(y,)- sell the y"th unit for $p(y"). Finally sell the y"th unit for marginal ply Mc(y) coSt, $p(y). p(y"") ply yy y y

First-degree Price Discrimination p(y) y $/output unit MC(y) y p(y) y y p(y) p(y) Sell the th unit for $ Later on sell the th unit for $ Finally sell the th unit for marginal cost, $ y p(y). y p(y). y p(y)

First-degree Price Discrimination Output unit The gains to the monopolist on these trades are: p(y)Mc(y), p(y)Mc(y) p(y') and zero ply Mc(y) p(y"") ply yy y y The consumers'gains are zero

First-degree Price Discrimination p(y) y $/output unit MC(y) y p(y) y y p(y) p(y) The gains to the monopolist on these trades are: and zero. p(y) − MC(y), p(y) − MC(y) The consumers’ gains are zero