The Chicago Stock Exchange (CHX) is a marketplace where people buy and sell stocks. People who want to buy stocks go to the exchange, pick a stock (a piece of a company), and then buy it for a certain price. They can then keep that stock for as long as they want or until they sell it - when they sell it, they get money back. They can also buy stocks using a broker, which is like a middle man - they pay the broker a fee to buy the stock, and they get money back when they sell it. On the other hand, people who want to sell stocks go to the exchange, pick a stock, and sell it for a certain price. They can keep doing this as long as they have the stock, until they decide they don't want it anymore. The Chicago Stock Exchange is where the buying and selling of stocks happens - it's like an auction, where people come to buy and sell stocks, and the prices of the stocks go up and down depending on how much people want to buy or sell them.