內部人在訂定交易計畫時並不知悉公司的重大訊息，但於計畫執行中得知公司重大訊息，若繼續執行交易計畫是否構成內線交易？在美國法之下，上述的問題涉及內線交易之構成究竟應採「利用說」或「知悉說」的爭議。聯邦巡迴上訴法院對此問題之意見分歧，直到2000年聯邦證券管理委員會頒佈Rule 10b5-1採用「知悉說」的觀點，然而為避免採知悉說可能使構成內線交易之範圍過廣，因此明訂若證券交易係基於「預定交易計畫」，則不構成內線交易，亦即將「預定交易計畫」明訂為免責抗辯事由。預定交易計畫在證券交易實務並不罕見，我國現行證券交易法制並未將「預定交易計畫」明訂為免責抗辯事由，未來的證券法制是否有參考美國法而引進該抗辯事由之必要？本文擬以比較法學為研究方法，並以美國法與歐盟法為比較研究對象，本文擬於現行證券法制的架構下，評估有無將「預定交易計畫」抗辯事由予以明文訂定之必要，並提出本文的建議。

The SEC adopted Rule 10b5-1 to define what it means to trade securities on the basis of material nonpublic information i.e. insider trading. Rule 10b5-1 also specifies exclusive affirmative defenses for one charged with insider trading, the essence of which are that there is no violation if the trade was made pursuant to a pre-arranged trading plan, even if the seller or buyer later became aware of the information before the trade was make. However, some news report that the insiders use pre-arranged trading plans as safe harbor to cover their illegal insider trading, therefore the insiders beat the market and make great profits from these trading. In this article, it finds out the origin, application, validity, and potential misuse of pre-arranged trading plans under U.S. securities regulations. Then it introduces how EU laws deal with this problem. Based on that, it evaluates the necessary of transplanting pre-arranged trading plan as an affirmative defense to insider trading into Taiwan legal regime.