國際反避稅法案對企業投資決策與最適企業所得稅率 之影響

Abstract

根據經濟合作發展組織與 G20 頒布的稅基侵蝕與利潤移轉行動計畫，中華民國即將實施符合國際標準的反避稅法案與共同申報準則。本篇論文以理論模型探討此一系列反避稅法案實施後，對於企業國際投資決策以及最適企業所得稅率之影響。在論文所建立的理論模型中，政府除了能夠決定國內企業所得稅率以外，也能夠決定為了調查避稅行為所付出的努力程度。 根據此篇理論模型的推論結果，我們發現法案實施可能有效降低企業的避稅行為。其影響程度視政府調查避稅行為的成本以及國內投資的價值而定。除此之外，我們也發現投資是否流回母國則受到母國與他國投資環境的差異影響。至於最佳所得稅率的部分，若政府比較在意國內投資，則應將企業所得稅率設得越低越好；若政府比較在意稅收，則應將企業所得稅率設在一個夠高但仍舊能夠吸引國內投資的程度。

According to the Base Erosion and Profit Sharing (BEPS) project proposed by OECD and G20, R.O.C. is going to adopt the Common Reporting Standard (CRS), which is a global information standard that aims to combat tax avoidance. To better understand the influences of CRS, this thesis establishes a theoretical model to study how the anti-tax-avoidance rules affect the firms’ tax avoidance activities and their decisions on whether to invest in foreign countries or in the home country. In the model, the government determines the domestic corporate income tax rate; it can also spend effort to investigate the firms’ tax-avoidance activities. We find that the implementation of the anti-tax-avoidance rules may decrease the probability of tax avoidance by firms. The effect depends on the marginal investigation cost of the government and the value of domestic investment. We also find that whether investments flow back to the home country depends on the relative attractiveness of the home country’s investment environment compared to those of foreign countries. As to the optimal domestic corporate income tax rate, the government should set the tax rate as low as possible if it cares more about domestic investment. If it cares more about tax payments, it should set the tax rate at a level that is sufficiently high, but still retain domestic investment.