An IPO's Grey Market Premium (GMP) serves as an unofficial gauge of the market's perception of the company prior to its formal listing. It shows the price, typically higher than the issue price, at which IPO shares are being exchanged informally on the black market. While a low or negative GMP could signal muted or poor sentiment, a positive GMP indicates that investors anticipate the company will list at a premium.
GMP shouldn't be seen as a reliable indicator of listing gains, though. Unofficial and unregulated, grey market transactions are mostly influenced by traders' liquidity, market sentiment, and short-term demand. Depending on membership numbers, general market conditions, and news flow surrounding the business or industry, the premium may change every day.