Regulations for the Computation of Business Tax for Dual-Status Business Entities Article 3

The proportion of input tax not deductible from output tax in the current period or in the current year depicted in this Act (called the "non-deductible ratio") shall mean the net sales amount of tax-exempt sales plus the net sales amount subject to Section 2, Chapter IV of the Act as a percentage of the total net sales amount for each period. However, the sales amount of land, government bonds as well as securities subject to transaction tax shall be excluded from the aforementioned calculation.The net sales amount referred to in the preceding paragraph shall mean the balance of the total sales amount minus returns and discounts.
中文原文 兼營營業人營業稅額計算辦法第3條
本辦法所稱當期或當年度進項稅額不得扣抵銷項稅額之比例(以下簡稱不得扣抵比例),係指各該期間免稅銷售淨額及依第四章第二節規定計算稅額部分之銷售淨額,占全部銷售淨額之比例。
但土地及各級政府發行之債券及依法應課徵證券交易稅之證券之銷售額不列入計算。
前項銷售淨額,係指銷售總額扣減銷貨退回或折讓後之餘額。

English translation for reference only; the Chinese text prevails. Not legal advice.