租稅對企業組織型態選擇所產生的影響以及其造成的福利損失，不論是理論上的探討或實證上的估計都非常重要，但針對台灣租稅制度對企業所造成的組織型態選擇影響，則缺乏相關研究。本研究利用財政部以行業和組織型態區分的營利事業所得稅申報資料，估計台灣所得稅制對企業組織型態選擇的影響。本研究發現，組織間的所得稅差異會影響企業在不同組織型態間的分配，惟其影響主要是企業的營收和應說所得，對企業家數的影響則較有限。本研究並利用估計值推估組織選擇扭曲所產生的效率損失，兩稅合一前企業投資所得面臨營利事業所得稅和個人所得稅的重復課稅，但獨資企業無法像公司一樣，利用保留盈餘規避個人所得稅，因此面臨較高的有效稅率。此一租稅差異因此導致顯著的效率損失。兩稅合一後，投資所得不再重複課稅，獨資企業投資所得的有效稅率已接近公司投資所得的有效稅率，因此不同型態問所得稅差異所造成的效率損失已明顯降低。

Previous studies document the taxation effect on firms' organizational choice and the welfare losses associated with this organizational distortion. However, studies examining firms' organizational distortion due to Taiwan's tax system are rare. This study utilizes industry-level data from profit-making enterprise income taxes to estimate the tax effect on firms' organizational choice. The estimates reveal that the ratios of sales and taxable income in each organizational form are affected by the tax gaps between organizations, implying that the distribution of the firms' business activities among different organizations are affected by the tax gaps. Based on the estimates, this study also evaluates the efficiency of firms' organizational distortion from tax differentials between organizations and finds that the efficiency loss was substantial before the 1998 tax integration bur was lessened by the tax integration.