本文嘗試在移轉訂價的規範下研究兩國政府與跨國企業間的租稅競爭行為,並將資訊不對稱的現象引入此租稅競爭模型中。透過設計一個由利潤稅率 ($t$) 與定額移轉 ($T$) 組成的租稅組合,分析政府在給定的常規交易原則(市價法)與不同的互動模式下,如何在''資訊租取得''與''稅基極大''的取捨中對具有隱藏資訊的跨國企業設計最適的租稅清單。

透過共同代理模型(Common agency model)的應用，
本模型得到的發現如下:
(1).在完全資訊下, 當政府能透過常規交易原則限制企業進行利潤移轉的行為時,由於利潤稅率在此時仍會對該國的稅基產生負面影響，為了使租稅收入極大,政府將會透過定額稅對企業課稅。
而最適稅率將維持在最低水準, 成為政府極大化該國稅基的工具。
(2). 在不完全資訊的環境中,　如果政府能夠在租稅組合上進行完全的合作, 且此時外生移轉訂價完全相同,政府會因為企業執行利潤移轉的行為消失而完全以"取得企業隱藏資訊"做為主要的課稅策略, 形成典型的代理人問題；然而，當兩國政府的移轉訂價不同，並且受制於某一國際組織的規範進行租稅上的協調時，國際組織將會衡量產量扭曲與資訊租取得對整體稅基的影響, 做為設計最適租稅的主要參考。本文發現，如果課稅對企業產量的變動百分比不會很大時(小於1/2),國際組織將會透過扭曲進口國的稅基來取得企業在出口國的內部資訊, 使均衡稅率介在[0,1)之間。
(3).
最後, 若兩國政府對具有隱藏資訊的企業進行非合作的租稅競爭，在市價法下,由於出口國對企業產生的扭曲不會影響該企業在另一國的稅率選擇,因此僅能以取得企業內部資訊租做為設計最適租稅的主要策略;另一方面, 因為進口國所受到的隱藏資訊只來自於產量的變動,
若該變動的方向由於與完全資訊時極大化稅基的方向相同,在沒有限制進口國的補貼上限的情況下, 進口國將會透過補貼的方式進一步扭曲企業的產量,使其接近極大化該國稅基的產量水準。

We study the problem of two governments who want to impose tax schedule combined with profit tax rate and lump-sum tax on a vertical integrated multinational enterprise
under transfer pricing regulation non-cooperatively . When the multinational enterprise's cost is complete information,
the bset stragtegy for the governments is to use lump-sum tax to collect the tax revenue and expand their tax base by reducing the profit tax rate.
Besides, we also examine how the governments design the optimal tax schedule if the cost is private information.
When the two governmente are cooperative and the transfer pricing rules are identical,
the cooperative government's best strategy is to design a nonlinear tax schedule to extract multinational's private information; however,
when the transfer pricing rule are not the same, the cooperative government will have to weigh the tradeoff between the gain of rent extraction and the distortion of the tax base.If the distortion of tax base is not too much, the optimal profit tax function will increase with the multinational's cost. Finally, we apply the common agent model to study the non-cooperative case when multinational has private information. Since the two government cannot use their tax scheule to affect the multinational's choice on other country's tax rate, two governments will still implement rent extraction stragtegy as their optimal tax schedule, which further reduce the multinational's output level.

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