How to predict IPO Listing Price from GMP?

Investors use GMP to predict the listing price of an IPO. For example, an IPO is offered at a price of Rs 100 and in the Grey Market the stock is trading at Rs 20 GMP.

In this case, the expected IPO Listing Price is Rs 100 + Rs 20 = Rs 120 per share. However, the actual Listing Price of the company may be higher or lower than the estimated Listing Price.