In the stock market, what is the concept of grey marketing?

Grey marketing is a trade of something legal but through unofficial and unauthorised distribution channels. In contrast, black marketing is a trade of illegal goods or services through illegal channels. The grey market of goods is to import and sell products through market channels which are not authorized by the manufacturers. It occurs when the prices of a product differ significantly in different countries. The grey market of securities markets and IPO (Initial Public Offer) is to buy and sell the shares to be allotted in the future. Once the trading is done in the grey market at a stipulated price, the seller must deliver the sold number of shares to the buyer on the day of listing to honour the commitment.