什么是市场

某种工具，可以使买方和卖方相互进入，以达成契约交换财货及服务。市场一词，原本指涉产品买卖的一处具体地方；现在市场一词则指涉任何场合，不论是多麽抽象或多麽遥远，只要能够促成买卖双方完成交易即可算数。例如伦敦和纽约的商品交易所（commodity exchanges），就是交易员透过电话、电脑连线及直接喊价而构成的跨国性市场。市场交易的标的物，不只包括看得到摸得着的商品，例如谷物和牲畜，也包括抽象的金融商品，例如证券（securities）和货币（currencies）。古典经济学致力於发展「完全竞争」的理论，他们设想的自由市场，是一处大批买方和卖方能轻易沟通及交易商品的地方；在这样的市场中，价格完全由供给和需求（supply and demand）所决定。但在1930年代以後，经济学家的关注点已转移到「不完全竞争」，认为供给和需求并不是影响市场运作的仅有因素。在不完全竞争中，买方和卖方的数量是受到限制的，竞争产品是相互区隔分化的（透过不同的设计、品质和品牌），而且会设下障碍来阻挡新进者加入市场。

market

Means by which buyers and sellers are brought into contact with each other and goods and services are exchanged. The term originally referred to a place where products were bought and sold; today a market is any arena, however abstract or far-reaching, in which buyers and sellers make transactions. The commodity exchanges in london and New York, for example, are international markets in which dealers communicate by telephone and computer links as well as through direct contact. Markets trade not only in tangible commodities such as grain and livestock but also in financial instruments such as securities and currencies. Classical economists developed the theory of perfect competition, in which they imagined free markets as places where large numbers of buyers and sellers communicated easily with each other and traded in commodities that were readily transferable; prices in such markets were determined only by supply and demand. Since the 1930s, economists have focused more often on the theory of imperfect competition, in which supply and demand are not the only factors that influence the operations of the market. In imperfect competition the number of sellers or buyers is limited, rival products are differentiated (by design, quality, brand name, etc.), and various obstacles hinder new producers' entry into the market.