Is trading in Grey Market illegal?

Yes, trading in the Grey Market is illegal. Grey Market is an unofficial and unregulated market, and all transactions in the grey market are based on mutual trust between the parties.

It is true that investors use GMP to get an idea of the listing of IPO shares. However, in many cases the GMP can be manipulated, especially for smaller issues, to encourage more and more investors to subscribe to an IPO. Therefore, the market regulator SEBI advises not to buy and sell IPO shares or applications in the Grey Market.