我國於民國 77 年增訂證券交易法第 157 條之 1，明文禁止具特定身分之人，利用內部消息買賣公司股票圖利之內線交易行為，目的即在於維護證券交易市場之公平性，以達健全我國證券市場即資本市場發展之立法目的。 新修法已進一步強調行為人實際知悉的重大消息，該消息除須達明確程度外，更須具備對股票價格有重大影響或對正當投資人的投資決定有重要影響「具體內容」，是在歷次修法一再強調消息應具「重大」、「明確」及「具體內容」等要件導引下，顯見立法者係嚴格要求內線交易之重大消息，其「具體內容」是必須對公司股票價格有重大影響或達到對「正當投資人」之投資決定有重要影響，始得限制實際知悉重大消息之內部人從事交易。由於是否構成重大消息乃以正當投資人對消息是否對其投資決定有重要影響威一具，因此，是否為重大消息，應立於正當投資人之視角，實質審究行為人實際知悉之消息其具體內容，是否對正當投資人之投資決定有重要影響。然而，觀之目前我國相關法規、判解函釋對正當投資人之定義均付之闕如，則仍無法使「重大影響其股票價格之消息」之定義趨於明確。蓋在我國內線交易所涉刑責重大，自應符合「罪刑法定原則」及「構成要件明確性原則」之要求，使行為人得事先預見其行為之可罰性，以保障人權。故何謂「正當投資人」此構成要件誠值吾人關切究明，俾使人民有法可循，避免形成資本市場寒蟬效應，否則將有違我國制定禁止內線交易規範，以健全我國證券市場發展之立法目的。

Taiwan in 1988 amdned Article 157-1 the Securities Exchange Act, expressly prohibiting a specific identity of the people to trading in company shares for profit of the transactions by using insider information. The purpose of the amendment of Article 157-1 is to maintain the fairness of the sceutities market in order to achieve a soundness copitl market. The Article has been further highlighted that the violator of insider trading mshould actual knowledge of the materials information. In addiotion to the clarity clear of law, the materical information must have had a significant impact on stock prices or have a major impact on "specific content" related to investment decision making process by the reasonable investor. Beause the guide leaded by the previous amendend of the Article repeatedly stressed that the material infoamation should be a "significant", "clear" and "specific content", the legislators stringently required the "specific content" of material information is to have a significant impact on the listing company's stock price or make the influence in making investement decision to the reasonable investors, before limiting the person who have the actual knowledge of the material information to have a stock transcaion. Since constitute major news denominated investors if there is a legitimate message in their investment decisions with an important impact Viagra, therefore, whether it is big news, investors should remain the proper perspective, the essence of the trial study perpetrator actual knowledge of its message specific content, whether legitimate investor's investment decisions have a major impact. However, the concept of the present, China's relevant laws and regulations, Prejudication letter Interpretation of lacking the proper definition of the investor are paid, you still can not make "a significant impact on its stock price's message" that tends to define clear. Cover major criminal implications of insider trading, since should meet the requirements, "the principle of legality" and "Elements of clear principles" of that behavior people have to anticipate their acts can be fined, so as to safeguard human rights. What it is "legitimate investors" Elements of this study Ming Cheng value 吾人 concern to enabling people follow the law, to avoid the formation of capital markets chilling effect, otherwise the country would be contrary to legislation prohibiting insider trading norms, legislation to improve China's securities market development purpose. This paper first discusses "rational investor" on the definition of the US Securities Exchange Act and scope, and research of "legitimate investor" concept similarities and differences with the United States "rational investor" meaning, the article discusses the US judicial practice and finds "rational investment people "should have the condition, as defined in our practice Prosecutor reference cases of legitimate investor standards, and on my card in case of Prosecutor justified cases the burden of proof of the responsibility of investors to comply with human rights ensure and improve our stock market trading environment.