A grey market is a market where there is trading of a stock that is about to be issued for the first time, before it’s issued. Grey market trading is risky because sellers’ don’t know how many shares they have – ie they’re selling shares they don’t own yet – and buyers don’t know what the final issue price is going to be when the allocation is complete. It can also refer to the pre market session when orders are being matched before the opening of the market.
