如何使企業所負擔之租稅成本降至最低之租稅規劃，對於企業的生存與競爭具有莫大的影響力。個案公司以境外公司之名義報價與接單，並透過OBU帳戶收受佣金收入，將利潤保留在境外公司，但營業費用卻於台灣公司認列，使得因三角貿易賺得之佣金收入是否歸屬於境外來源所得而免稅，一直為爭議性之話題。 　　為避免將利潤保留在境外公司而不匯回，擬於所得稅法修正草案中將決議分配股利時才認列投資收益，改成依照財務會計上之權益法認列投資收益。並配合響應政府提倡亞太營運中心計劃及經發會提出健全資金回流機制，增（修）訂促進產業升級條例第七十條之一及兩岸人民關係條例第二十四條第二項，並開放OBU得與大陸地區金融機構直接通匯。 　　根據以上結論，本研究提出建議如下： 　　一、對企業界之建議 　　企業進行國際租稅規劃時，應把握合法性、注重實質、評估規劃之成本效益及考慮相關法令變遷之風險等四項原則。 　　二、對政府修法之建議 　　　1.發展台灣成為營運總部之租稅配合措施 　　　　(1)加強簽署國際租稅協定 　　　　(2)建議評估營利事業所得稅由屬人主義改採屬地主義之可行性 　　　2.對租稅政策之建議 　　　　(1)反租稅天堂措施之建議 　　　　(2)重新檢討所得稅法等有關涉外法規之適用 　　　3.我國現行稽核制度的改進意見 　　　　(1)加強國際租稅人才的培訓 　　　　(2)提昇稅務稽查技術 　　　　(3)增強稽核人力素質 / Using case study method and by interviews with field experts, this thesis studies the application of OBU (off-shore banking unit) in international tax planning. Planning to decrease tax costs has long been an important task for multinational companies to compete in the international market. To avoid paying domestic taxes, companies can structure transactions by the name of offshore subsidiaries and receive commissions through their OBU accounts. Consequently, profits are reserved in the offshore companies but costs of running business are claimed in Taiwan's tax returns. Under certain circumstances, commissions earned from this kind of triangle trading are tax-free, causing substantial losses of tax revenues to Taiwanese government. The thesis discusses this controversial issue relating to commissions from triangle trading. 　　To encourage remitting back profits generated in overseas, the tax law for taxes on investment income should be changed. This thesis suggests the use of equity method for recognizing investment income for tax purposes. Further, the regulation on banking operations between Taiwan and China also needs to be revised to expedite the transfer of fund across the strait. The thesis suggests the opening of direct remittance between Taiwan's OBUs and China's banks. 　　In summary, in devising an effective tax planning, companies should take into account both tax and nontax costs, and keep abreast of the risks of changes in tax laws and governmental policies. As for the government to develop Taiwan as the headquarter of global operation, promotion of the international tax agreements is essentially important to help firms avoid double taxation. Further, to attract more international companies investing in Taiwan, the government should evaluate the feasibility and impacts of shifting the taxation principle of corporations from worldwide taxation to territorial taxation.

跨國企業為了各種考量而紛紛前往海外成立境外公司（offshore company），其中租稅天堂（tax havens）因稅負較低且公司註冊方便等因素，故跨國企業成立境外公司的據點皆選擇租稅天堂，使得租稅天堂近年來聞名於全世界。 　　而我國自從民國七十六年七月放寬外匯管制以及僑外投資與鼓勵對外投資以來，對外投資活動日益興盛，租稅天堂的運用也因此伴隨增加。根據本研究整理自公開資訊觀測站的資料，且利用統計方法分析，我國跨國企業自民國八十七年至九十三年為止，運用租稅天堂有上升的趨勢且多集中於加勒比海地區，個別國家或地區則是偏重於英屬維京群島（British Virgin Islands）、開曼群島（Cayman Islands）以及薩摩亞（Samoa）。另外，為了探討我國跨國企業運用租稅天堂之特性，採用計量模型為追蹤資料（panel data）。根據實證結果，影響我國跨國公司前往運用租稅天堂之因素計有公司規模、非租稅天堂互補性以及非租稅天堂稅率。 　　本文乃針對我國政府目前對外之稅制政策與上述結論，作一歸納並提出幾點建議，期盼做為我國政府對於租稅天堂因應之策。並開創我國政府與我國跨國企業雙贏之局面。

近年來各國跨國企業利用對外投資控股架構設計進行租稅規劃，複雜的跨國結構安排導致各國稅基嚴重被侵蝕，引起各界關注，故了解跨國公司如何規劃其投資控股架構有其必要性。基於國內尚未有實證文獻探究國際租稅規劃對我國跨國公司投資控股架構決策之影響，因此本文針對2010年至2014年台灣上市櫃公司之海外關係企業目前投資控股架構進行研究，以了解我國對外投資的投資控股架構設計概況。此外，本文進一步探究跨國公司為了進行國際租稅規劃，不同租稅屬性的上下層公司是否確實會有相對應租稅特性之公司搭配形成控股連結。 本文建構兩個迴歸模型，採用Tobit模型進行實證分析。模型一分析基本租稅因素對於跨國控股連結之影響，實證結果顯示跨國控股連結設計會受到租稅協定、上下層公司所在國稅率差距影響。而模型二檢視國家組合間之租稅搭配相關變數對跨國控股連結的影響。結果顯示，上下層公司所在國的租稅環境確實會影響與其形成控股連結之所在國家的區位選擇。 / In the recent years, multinational corporations using the design of investment holding structure to do the tax planning. The complicated investment holding structure result in the tax base being damaged, and it draws the attentions of all walks of life. Therefore, there’s necessity to understand how the multinational corporations plan their investment holding structure. Due to the fact that there’s no literature which research the influence of international tax planning to our country’s multinational corporation investment holding structure decision have been proved. In order to understand how Taiwan’s multinational corporations plan their investment holding structure, we do the research against the investment holding structure of Taiwan’s listed companies from 2010 to 2014. Besides, we do the research more advanced on the international tax planning to see whether there will be companies with corresponded different tax characteristic that form an ownership links with the upper and lower companies of different tax characteristic. In this paper, we constructed two regression models, the Tobit random effect model is used to do the empirical analysis. The Model 1 analyzes the relation between the basic tax variable and the cross-border ownership links. The results indicate that the design of cross-border ownership links will be affected by tax treaty and the difference of tax rate between the upper and the lower countries. And the Model 2 examines the relation between tax collocation of country pair variables and cross-border ownership links. We found out that the tax environment where the upper and lower companies are located has truly affect the location choice of the country which the ownership link is linked to.