過去已有許多實證論文指出，擁有較高市占率的公司亦擁有較高的獲利性。然而，公司有兩種策略可以提高自身的市占率:一是採用競爭策略，二是採用合作策略。因此，本篇論文欲從市占率的觀點探討當公司處於一個完全競爭市場且該市場內的其他公司均銷售同質性很高的商品/服務時，公司究竟要採取哪種策略才會對公司最有利。我們會根據會計學的利潤公式和機率論的期望值建立一個「市占率-公司獲利期望值」的數學模型來進行分析。結果顯示，擁有較高期望值或市占率的公司，應採取競爭策略;反之則應採取合作策略。這個結果亦使得市場維持在完全競爭的狀態。

Higher market share means higher profitability, this result has already been proved by many empirical papers in the past years. However, there are two strategies that can promote the market share：One is competition, the other is collaboration. The purpose of this paper is comparing these strategies to see which is more beneficial when corporations are in a fully competition market and selling highly homogeneous products/services. I will introduce the concept of “expected value” and build up a “market share-expected value of acquiring the profit model” to analyze it. As a result, corporations with higher/lower expected value of acquiring the profit or market share are better adopting competition/collaboration strategy. This result will remain market in competition.

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