Pre-market means before the market. While some financial markets, like foreign exchange markets, never stop trading, most individual stock markets have defined trading hours. That’s because the stock exchanges are open generally for the working day of the time zone in which they are located. Pre-market generally refers to the early hours just before that stock market opens.
In many cases, company announcements like earnings reports will be released pre-market. That gives traders and investors time to digest the information before the regular stock market session opens. Some brokers and exchanges may offer pre-market trading before the regular stock market opens, and although volatility and liquidity tend to be much lower during the pre-market, these sessions can be used to gauge the general direction of a market or the strength or weakness of an individual stock.