Comment on the following Most countries have regulations that prohibit "insider trading"

Many countries have regulations against insider trading. Even if market is found to be in semi strong form insider trading regulations should be needed.

Semi strong form of market efficiency indicates that, all the publicly available informations are already reflected in the stock prices and it is impossible to outperform the market using available public informations. However this means that if some one have private information, he can outperform the market.

Insider trading is trading on private informations as it is the informations an employee or a trader obatain before the company publish it. Hence as per Semi strong form, it doesnt violate the theory. Hence to tackle this situation even if in a semi strong form of market, regulations are a must.