A stock exchange is a place where stocks and bonds are bought and sold. Stocks represent shares in a company and their value depends on what people think the worth, or future worth, of the company is. It was at the stock exchanges that the loss of confidence in the economy first began to show. Everyone wanted to sell and no one wanted to buy so the prices kept dropping. The value of shares in various companies went down by $30 billion. The price of wheat which was at $1.65 a bushel in 1929, tumbled to 30 cents a bushel by 1931.