ccer微观经济学课件18-1127

MC(y)
p(y) y’ y’’
p(y’’’)
y’’’
y
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First-degree Price Discrimination
p(y’) p(y’’)
The gains to the monopolist on these trades are: p(y’)-MC(y’), p(y’’)-MC(y’’), and zero.
比比起没有价格歧视的垄断，就有了进步
Examples of First-degree Price Discrimination
常⻅见的一一级价格歧视就是拍卖，这样买家能够得到最大大的信息量，竞价最高高的人人报的就是他的支支付意愿，一一件一一件拍卖，实现了一一级价格歧视
Auction Salesman negotiate price with each customer May not always be practical – do not know willingness to pay – too costly
$/output unit 3) Charge A for x10, charge A+C for x20, profit=2A+C - able to let consumers self-select themselves - but 2A+C<A+B+C
我还是定两个价格，但是同时对 P2不要这么严厉，不 把他的全部剩余榨取，而而是让他选择 X2所得的剩余不 比比他选择 X1所得的剩余少，这样迫使他自自愿选择 X2。 不允许我进行行人人的歧视，我就通过量的歧视获得了二二级 价格歧视，但是这种定价策略利润还不如方方法(2)
p(y)
y’’’
y
First-degree Price Discrimination
First-degree price discrimination gives a monopolist all of the possible gains-to-trade, leaves the buyers with zero surplus, and supplies the efficient amount of output. Allowing a monopolist to price discriminate improves efficiency
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Types of Price Discrimination
1st-degree: Each unit is sold at a different price. Prices may differ across buyers. 2nd-degree: Price paid by a buyer can vary with the quantity demanded by the buyer. But all customers face the same price schedule.
D’’
m
C’’ x 20 quantity
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Examples of Second-degree Price Discrimination
Telecommunications packages Shopping membership Water / electricity price … 2nd-degree discrimination can also occur in the dimension of quality – Different prices for different seats in a theater – Different prices for economy class vs. business class seats in planes
即对人人歧视也对量歧视，不同的人人买，买不同的量价格都不同 不同的量收不同的价，可能量大大打折也可能量大大加钱
E.g., bulk-buying discounts.
3rd-degree: Price paid by buyers in a given group is the same for all units. But price may differ across buyer groups.
E.g., senior citizen and student discounts
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.
把 X1定的低一一些，然后对 X2的定价要使得高高端消费者选择 X2所得剩余大大于 B’
B’ A’
C’
D’
x 10
x 20
quantity
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Second-degree Price Discrimination
$/output unit 4) Reduce x10 so A is reduced a little bit to A’, but C can be increased by a lot to C’+D’ - Persons 1 and 2 are still identified, charge A’ for x10, charge A’+C’ +D’ for x20 - profit=2A’+C’+D’ =A+C+A’+阴影 B’ = 2A + C +阴影-绿色 Compared with 2A+C? C’ A’
B A x 10 C x 20 quantity
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Second-degree Price Discrimination
$/output unit 4) Reduce x10 so A is reduced a little bit to A’, but C can be increased by a lot to C’+D’ - Persons 1 and 2 are still identified, charge A’ for x10, charge A’+C’ +D’ for x20 - profit=2A’+C’+D’ =A+C+A
显然，这比比策略(3)更好
D’
经济舱为什么服务差，不是因为服务好了他成本高高，而而是因为如果把经济舱服务搞好 了，高高端客户就不去买商务舱了。很多时候，不是说不能提供更好的服务，而而是故意把 服务的档次拉开。一一等座二二等座服务就是不一一样，这样才能刺激高高端客户去买头等座。
x 10
x 20
quantity
12
An Example
Two consumers – Person 1 has low willingness-topay – Person 2 has high willingness-topay Assume MC=0
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Second-degree Price Discrimination
MC(y)
p(y)
p(y’’’)
y’ y’’ y’’’ y So the sum of the gains to the monopolist on all trades is the maximum possible total gains-to-trade. The consumers’ gains are zero.
First-degree Price Discrimination
The monopolist gets the maximum possible gains from trade.
First-degree price discrimination is Pareto-efficient.
PS
MC(y)
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Second-degree Price Discrimination
$/output unit Profit is maximized at x1m B’’ A’’ x1
profit = 2A’’+C’’+D’’
随着 X1左移，一一段使得利润变大大一一段使得利润变小小，就是当这两段⻓长度相等的时候，利润达到最大大 此事得到的利润高高于统一一定价，因为统一一定价的时候，只服务高高端客户，低端客户被放弃了 而而二二级价格歧视下，同时服务了高高端客户和低端客户
ቤተ መጻሕፍቲ ባይዱ
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 earn higher profits?
这种定价策略下，P2若买 X2其剩余为0，P2若买 X1其剩余为 B，因此 P2会选择买 X1，歧视失败 干脆不定两个价格，直接定一一个量，卖一一个价格，就卖 X2，收 A+B +C 的钱，把低端消费者排除市场外，榨取高高端消费者的全部剩余
A x 10
C x 20 quantity
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Second-degree Price Discrimination