A stock symbol is a series of letters assigned to a security for trading purposes. Investors started using them to streamline hundreds of trades being made by the minute.

On the Nasdaq, a fifth letter is added to stocks that are delinquent in certain exchange requirements: for example, in ACER.W, the first four letters comprises the stock symbol for Acer ...

If X ever goes public, Musk may have a shot at getting the X ticker symbol. The current X holder is U.S. Steel , which announced on Monday that it was being acquired by Nippon Steel in a $14.9 ...