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.