本文研究內生化事先承諾選擇下，雙占廠商進入市場時點的兩階段賽局。兩家廠商在第一階段同時且分別選擇是否要事先承諾進入市場的時點，若廠商決定要事先承諾進入市場的時點，則其必須付出一個承諾成本。在賽局的第二階段，若廠商選擇要事先承諾，則在期初承諾一個進入市場的時點；若廠商選擇不事先承諾，則隨著時間的經過，廠商可以在任何一個時點進入市場，在進入市場之後，廠商在每個時點決定其產品的數量。在進入市場成本隨時間經過而遞減的假設下，研究發現當承諾成本相對較大時，均衡結果為兩家廠商都選擇不事先承諾進入市場的時點，雙占廠商均衡時依序進入市場且「利潤均等」；當承諾成本相對較小時，均衡結果為一家廠商選擇事先承諾進入市場的時點而成為先進廠商，另一家廠商選擇不事先承諾進入市場的時點而成為後進廠商，均衡時存在「承諾優勢」、「先進者優勢」。

This paper investigates a timing game of market-entry with endogenous precommitment choices. In the first stage, two firms simultaneously and individually decide whether or not to precommit to their respective timing of market-entry at the beginning of the game. If a firm has decided not to precommit to its timing of market-entry, then it can flexibly alter its timing of market-entry in the second stage. After a firm’s entry, it chooses its quantity supplied throughout each instance. The results show that both firms decide not to precommit to their timing of market-entry and sequentially enter the market in equilibrium when a firm’s commitment cost is relatively high. When a firm’s commitment cost is relatively low, only one firm decides to precommit to its timing of market-entry and behaves as a leader. The other firm decides not to precommit to its timing of market-entry and behaves as a follower. There are “commitment advantage” and “first-mover advantage” in equilibrium.