“After the bell” is basically a financial slang used for activity occurring after the close of the stock market, The New York Stock Exchange (NYSE) closes its trading day with the ringing of a bell including after-hours trading, illegal late trading of open-ended funds (during the mutual fund scandal of 2003), earnings announcements, acquisition plans and merger agreements. The term originates from the ringing of the bell on the NYSE, which denotes the open and close of trading sessions.The New York Stock Exchange (NYSE) closes its trading day with the ringing of a bell.
Generally, important, company-specific news is released after the bell to give investors time to dig through the information and make informed buy and sell decisions. In addition, announcements after the close of trading provide order and stability to the markets. News released during the trading day or before the bell (prior to the start of the trading session) could generate negative consequences, like panic-selling, unbridled speculation and buy/sell imbalances. Pertinent news announced after the bell leads traders to trade stock based on the fresh information, although in very thin markets. However, it should be noted that traders may trade stock after the bell for a variety of reasons, which may not be related to company news releases.