公司稅，租稅天堂與國際租稅競爭

Abstract

隨著全球化的來臨，使得租稅天堂的重要性與日俱增。這種現象也讓跨國企業有 更多的機會將其利潤轉移至低稅負的區域，並改變了國際上跨國公司與政府間的 策略賽局。另一方面，由於異質的成本結構對國際租稅競爭程度的影響相當深 遠，因此晚近許多文獻在成本異質的情況下，利用壟斷性競爭模型探討租稅天堂 是否應存在的議題。其中Krautheimand Schmidt-Eisenlohr (2011) [文後簡稱K-S-E 模型] 則認為租稅競爭會製造扭曲，讓稅率與公共財數量過低。當廠商生產力越 異質，這種由於和租稅天堂進行租稅競爭的負面效果也會越強，讓福利水準更加 低落。值得注意的是，為了簡化分析，K-S-E 模型所探討的是利潤稅制而非公司 稅制，而此一假定明顯與現實不符（參見研究計畫背景與目的之說明）。比較重 要的是，利潤稅制的課徵具有產出的中立性，因而不會扭取廠商的決策；然而公 司稅制的課徵不具中立性，所以會扭取廠商的產出決策，而且當公司稅率上升時 會產生所謂的配置生產效率效果，進而影響到租稅競爭的程度 [參見郭虹瑩 (2011)]，最後可能會改變K-S-E 模型所獲致的結果，不過利潤稅的課徵則無此一 效果。有鑑於此，本研究計畫擬在K-S-E 的模型中導入公司稅制，探討公司稅制 如何影響到國際的租稅競爭的程度、公共財提供，以及租稅天堂對一國福利水準 的影響，所獲致的結果再與K-S-E 模型作一對照。其次，本計畫亦可將K-S-E 模型擴展到探討兩國皆為大國的租稅競爭之模式，以及容許更多租稅工具的情 況。

With globalization tax havens have become more important. The increased opportunities for multinational firms to shift profits towards these low tax jurisdictions have changed the strategic tax game for international profits and pose new challenges to policy makers. In the real world, larger firms are more likely to use tax haven operations to exploit international tax differences. By the reason, Krautheimand Schmidt-Eisenlohr (2011) [hereafter K-S-E] study tax competition between a large country and a tax haven under the setting of a profit tax. However, in most economies, the corporate tax is a capital tax instead of a profit tax. The major difference between them is that the profit taxes are neutral, however, the corporate taxes are not neutral. Especially, levying the corporate tax will cause the differences in cost to the firms to increase, and hence give rise to the so-called allocative production efficiency effect referred to by Long and Soubeyran (1997), which will affect the extent of tax competition. By the reason, this project intend to extend the K-S-E model in several ways. Firstly, take the corporate tax into account and analyze how the role will the “allocative production efficiency effect” play on the tax competition wars. The second, two large but asymmetric countries could be considered. Allowing for firm entry and endogenous reallocation would give rise to an interesting trade-off. While a country could lose part of its tax base due to profit shifting, this could be the only way for it to keep production of very productive firms at home. Finally, to enlarge the set of tax instruments. Firm heterogeneity creates a problem for a government as it cannot discriminate between firms with different productivity levels. Thus any instrument that allows the government to treat firms asymmetrically may alleviate the pressures from tax competition.