資本所得所負擔的稅額之高低，以及稅負輕重對投資誘因的影響，向來為經濟學者所 關切。然而，由於有數種不同的租稅同時對資本所得課徵，而且，由於通貨膨脹、公 司融資政策、個人所得稅與公司所得稅併存、投資扣抵……等因素，使得吾人不易完 整地表達出資本所得的租稅負擔情形。 在經濟學上，往往用有效稅率（Effective tax rate）來表達資本所得的租稅負擔， 然而何謂有效稅率？在文獻上所討論的有效稅率，可大略地區分為兩大類：平均有效 稅率（Average effective tax rate）與邊際有效稅率（marginal effective tax - rate）。前者是指過去的年度裡，平均每一元的資本所得，負擔多少的稅額；後者是 指未來新增加一單位投資，其賺取的資本所得須負擔多少稅額。平均有效稅率適合用 來表達資本所得過去的稅負情形，但不適於用來衡量租稅對投資誘因的影響；而邊際 有效稅率表達出投資計劃之稅前報酬率，與資金提供者的稅後報酬率之差距，故適合 用來衡量租稅對投資誘因的影響。 本文鑒於一般文獻在討論有效稅率時，往往不加以定義所討論的究竟是平均還是邊際 有效稅率，以致常導致誤解，甚至有部份文獻誤用平均有效稅率，來探討租稅對投資 誘因的影響，因此，本文先對有效稅率一詞的意義，予以釐清；繼而討論各種有效稅 率的正確用途，並且說明邊際有效稅率，與投資誘因之間的關係；最後，本文也嚐試 估計我國資本所得的邊際有效稅率。

The purpose of this master thesis is comparison of the tax burden of Czech a Swedish employees. The first part describes tax systems of both analyzed states focusing on the taxation of income from employment according to the 2016 legislation in order to successfully perform the calculations in the following sections. The second, practical part is dedicated to the comparison of selected indicators. It consists of two parts. The first is focused on the calculation of average effective tax rate for various income groups and various types of taxpayers. The next part compares values of redistribution indicators, which are interval and global progressivity indicators (Lorenz curve, Gini coefficient). The final section is devoted to the comparison of conclusions of this thesis with conclusions of thesis with similar subject, that have been successfully defended.

The aim of this thesis is to compare effective income tax rate in Czech and Slovak republic. After introduction follows chapter which describes the tax systems in both countries with focus on personal income tax and social insurance. The third chapter defines indicators of effective labour taxation which are used for international comparison. Chapter four is comparing effective labour taxation in Czech and Slovak republic based on indicators defined in previous chapter. The fifth chapter is analysing inequality of income distribution and influence of income tax on redistribution. The progressivity of personal income tax in Czech and Slovak republic is measured by interval and global progressivity method. The conclusion is summarizing the outcomes of the thesis and suggests improvements for Czech tax system.