GCSE OCR Economics: Monopolistic Competition | 垄断竞争 考点精讲

📚 GCSE OCR Economics: Monopolistic Competition | 垄断竞争 考点精讲

Monopolistic competition is a market structure that combines elements of both competition and monopoly. It is one of the most common market forms in the real world, characterised by many firms selling differentiated products. This revision guide breaks down the key concepts required for GCSE OCR Economics, covering characteristics, short-run and long-run equilibrium, efficiency, and non-price competition strategies.

垄断竞争是一种兼具竞争和垄断特征的市场结构。它是现实中最常见的市场形式之一，特点是众多企业销售差异化的产品。本复习指南拆解了GCSE OCR经济学所需的要点概念，涵盖特征、短期和长期均衡、效率以及非价格竞争策略。

1. What is Monopolistic Competition? | 什么是垄断竞争？

Monopolistic competition describes a market where many firms compete, each offering a product that is slightly different from its rivals. Because each firm’s product is unique in some way, the firm has a degree of market power, allowing it to set its own price. However, because there are many substitutes, this power is limited.

垄断竞争描述的是一种市场：许多企业相互竞争，每家企业提供的产品都与其竞争对手略有不同。由于每家企业的产品在某种程度上是独特的，该企业拥有一定的市场势力，能够自行定价。但由于存在许多替代品，这种势力是有限的。

This market structure sits between perfect competition and monopoly. It is more realistic than perfect competition because products are rarely identical, and it is less concentrated than a monopoly. GCSE examiners expect you to know its defining features.

这种市场结构介于完全竞争和垄断之间。它比完全竞争更现实，因为产品很少完全相同；它也比垄断分散。GCSE考官期望你掌握其定义性特征。

2. Characteristics of Monopolistic Competition | 垄断竞争的特征

There are four main characteristics of monopolistic competition that you must memorise:

• Many buyers and sellers: The market consists of a large number of small firms, none of which dominates the market. Each firm has a relatively small market share.
• Product differentiation: Firms sell products that are similar but not identical. Differentiation can be real (quality, design, features) or perceived (branding, packaging, advertising).
• Low barriers to entry and exit: It is easy for new firms to enter the market when profits exist and to leave if making losses. There are few legal, technological or financial obstacles.
• Imperfect information: Buyers and sellers may not have complete knowledge of prices and quality, but information is generally better than in a monopoly.

垄断竞争的四个主要特征，你必须记牢：

• 众多买者和卖者：市场由大量小企业组成，没有一家占据支配地位。每家企业的市场份额相对较小。
• 产品差异化：企业销售相似但不完全相同的产品。差异化可以是真实的（质量、设计、功能）或感知的（品牌、包装、广告）。
• 低进入和退出壁垒：新企业在利润存在时容易进入市场，亏损时也容易退出。其间法律、技术或资金障碍很少。
• 不完全信息：买者和卖者可能不完全了解价格和质量，但信息通常比垄断情况下好。

Importantly, these features mean each firm faces a downward-sloping demand curve and acts as a price-maker, but must still consider competitors’ prices.

重要的是，这些特征意味着每家厂商面对一条向下倾斜的需求曲线，并作为价格制定者行事，但仍需考虑竞争对手的价格。

3. Short-Run Equilibrium and Profit | 短期均衡与利润

In the short run, a monopolistically competitive firm maximises profit where marginal revenue (MR) equals marginal cost (MC). This is the same profit-maximising rule as in other market structures: produce the quantity where MR = MC, then charge the price from the demand curve at that quantity.

在短期，垄断竞争厂商在边际收益（MR）等于边际成本（MC）处实现利润最大化。这与其他市场结构的利润最大化规则相同：在 MR = MC 的产量水平生产，然后根据需求曲线在该产量处确定价格。

If at this output average revenue (AR = price P) is greater than average total cost (ATC), the firm earns supernormal profit. The diagram would show a rectangle of profit between P and ATC at the profit-maximising quantity Q. If P equals ATC, the firm earns normal profit. If P is less than ATC, it makes a loss but may continue if price covers average variable cost.

如果在该产量下，平均收益（AR = 价格 P）大于平均总成本（ATC），企业获得超额利润。在图中，利润最大化产量 Q 上，P 与 ATC 之间的矩形表示利润。如果 P 等于 ATC，企业获取正常利润。若 P 小于 ATC，则出现亏损，但只要价格能覆盖平均可变成本，企业可能继续经营。

Because the product is differentiated, the firm has some loyal customers, so its demand curve is relatively elastic but not perfectly elastic like in perfect competition. Supernormal profits are possible in the short run.

由于产品差异化，企业拥有一定忠诚度客户，因此其需求曲线相对有弹性，但不像完全竞争那样具有完全弹性。短期超额利润是可能的。

4. Long-Run Equilibrium and Normal Profit | 长期均衡与正常利润

In the long run, the absence of barriers to entry means supernormal profit attracts new firms into the market. As new firms enter, they offer similar but differentiated products, which takes away customers from existing firms. This shifts each existing firm’s demand curve to the left (decrease in demand) and makes it more elastic due to more substitutes. This process continues until all supernormal profit is competed away.

长期中，由于没有进入壁垒，超额利润吸引新企业进入市场。随着新企业进入，它们提供相似但有差异的产品，夺走原有企业的顾客。这使得每家现有企业的需求曲线向左移动（需求减少），并因更多替代品而变得更富弹性。这一过程持续直到所有超额利润被竞争掉。

The long-run equilibrium occurs when the firm’s demand curve (AR) is just tangent to the ATC curve at the profit-maximising output where MR = MC. At this point, P = ATC, and the firm makes only normal profit. No further entry or exit occurs.

长期均衡出现在厂商

Published by TutorHao | GCSE Economics Revision Series | aleveler.com

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