market structure

这是一篇关于market structure的思维导图，主要对比了完全竞争市场（perfectly competitive）和垄断市场（monopoly markets）的特点、垄断产生及持续的原因等内容。

market structure

• perfectly competitive
  • characteristics
    • small firms
    • each firms has small market share
    • no barrier to entry
    • price taker
    • selling identical products
• monopoly markets
  • characteristics
    • 100% market share
    • high barriers to entry and exit
    • price maker
    • 附加：may have supernormal profits
  • why monopoly arises?
    • very low costs (economies of scale) -lower price-客户不会从其他的商家那里购买
    • large market share through merger and take over
    • monopoly exist at start, firm may have all the resources
  • why monopoly continue?
    • barrier to enter
      • legal barrier a patent(专利) or government act 如水电供应
      • scale of production（刚进入产业生产规模很小不足以竞争）
      • 同行已经形成了brand loyalty
    • barrier to exit
      • high sunk cost（如昂贵的机器设备）
      • long term contact to provide a product（有了长期提供产品的合同 不能违约）
    • monopoly的行为后果有哪些
      • high price（不在意cost 可以定高价）
      • low quality
      • less consumer choice
      • inefficiency（浪费资源 没有competition和生存压力，不在意）
    • why support monopoly?
      • 减少waste of duplication
      • help to gain supernormal profit to do market research and development
      • large scale of production-high efficiency and average cost
    • why against monopoly
      • low quality due to lack of competition
      • higher price due to price maker（100% supply is firm's supply)
      • slow to respond changes in demand