A stock symbol is a unique series of letters or numbers, used to identify a stock traded on a stock exchange. They are also sometimes referred to as stock tickers or ticker symbols.
Every traded stock will have its own stock symbol. The allocation of stock symbols varies from country to country, with some giving up to four characters to identify a stock, and others specifying a set number of characters.
A full stock symbol will contain both the stock’s symbol and details of the exchange or country in which it is traded. Microsoft on the NASDAQ, for instance, is often referred to as NASDAQ:MSFT or MSFT:US, whereas BP on the London Stock Exchange is BP:LON or BP:UK.
The name stock ticker derives from the days when stock symbols where used for transmitting prices using ticker tape.