信託契約明定信託利益之全部或一部之受益人為非委託人者，視為委託人將享有信託利益之權利贈與該受益人，依我國遺產及贈與稅法第5條之1規定，應對委託人課徵贈與稅，課稅的時點係以信託契約成立時。信託利益係來自於信託財產，信託利益除信託財產原本外，尚包括信託財產於信託期間產生的孳息，信託財產於信託期間能產生多少孳息，信託契約成立時通常並無法知悉，故在信託契約成立時，對信託財產的孳息課徵贈與稅，勢必須以估計的方式計算其價值。惟信託財產之樣態多變，以推計方法估價，難以使信託利益的價值客觀、合理，有違課稅公平的原則。若將信託利益的課稅時點，延至信託利益實現時，即無須以估計之方式課徵，而是以受益人實際獲配之信託利益課稅，避免納稅義務人藉信託作為租稅規劃的工具，以維護租稅之公平。又於信託契約成立時課稅，即認定信託財產的孳息於信託契約成立時即已移轉給受益人，依所得稅法第3條之4第1項規定，信託成立後信託財產發生的孳息即應併入受益人的所得課徵所得稅，當委託人綜合所得稅適用較高的稅率，其可利用稅率較低的受益人為其分散所得，以達到規避個人綜合所得稅的效果。若改以信託利益實現時課稅，在信託利益給予受益人前發生之所得，仍屬委託人之所得，應併委託人之所得課稅，即不致於產生委託人藉他益信託規避所得稅負。以信託契約成立時為課稅的時點，信託利益的價值估計顯不符合其經濟實質，有違量能課稅的原則，更產生諸多租稅規避空間，及不合理的課稅結果，若改採信託利益給付予受益人時課稅，即可免除上述的缺失，故建議信託利益的課稅時點，應改採受託人給付信託利益時課徵之。

Article 5-1 of the Estate and Gift Tax Act (in Taiwan) defines a trust contract, which is created under a fiduciary relationship in which benefit (includes principle and interest) does not distribute to the grantor totally, the grantor is subject to gift tax and the time of taxation is at the trust created.The trust property is the source of trust benefit, which includes principle (corpus) and interest (future income). Unlike principle, interest has not been realized. So tax collector only can estimate the values of those unrealized income at the time of trust contract created. Because there is no fair market value and the annual income is fluctuate from time to time. So, the value of trust interest is too hard to estimate correctly, reasonable, and fairly at the time of trust created. Besides, incorrectly estimation also violates the tax equity. If the time of taxation can be changed to the time of trust benefits realized instead of the time that the trust is created, the tax collector will be no need to estimate the trust interest, neither grantor can not avoid individual income tax by trust planning.At the time of trust created, trust benefit has transferred to beneficiaries, and the annual income of trust after trust created shall belong to the beneficiaries' annual individual income , even though trustee doesn't distribute income to the beneficiaries (Article 3-4 (1) of Income Tax Act in Taiwan). So, if the grantor's individual income tax rate bracket is much higher than beneficiaries', he can avoid individual income tax by separate his annual income to other beneficiaries. Unless, the time of taxation can be deferred to the time of trust income is distributed to beneficiaries (trust interest is realized), or trust income still belongs to grantor's individual income.The primary of this study is to discuss the time of taxation at the time of trust created can not reflect the trust benefit's real value, also gives taxpayers lots of chances to avoid individual income tax. In order to achieve tax equity, we recommend that the government can reconsider to change the time of taxation to the time of trust interest distribution.