The oldest and largest stock exchange in the United States, the New York Stock Exchange (NYSE) had its origins on May 17, 1792, when local brokers who had been buying and selling securities under a designated tree agreed to formalize their business transactions. The NYSE that most people would recognize today opened for business in 1825 at 11 Wall Street, New York City. At the time most shares traded were in canal, turnpike, mining, and gaslight companies. Though a few industrial securities were first traded on the New York Stock Exchange as early as 1831, it was another 40 years before the complexion of trading changed to a more industrial nature. As the nation became increasingly manufacturing oriented, the companies listed on the exchange reflected the economic shift. Today, if corporations wish to list their stocks on the NYSE, they must have a minimum of 2,000 shareholders, each of those original shareholders must have 100 or more shares, the corporation must be able to issue at least 1 million shares of stock, and it must also provide a record of earnings for the previous three-year period. The board of the stock exchange can make exceptions to these guidelines. Corporations may be listed with other stock exchanges (such as the American Stock Exchange) or they may allow stock in their company to be traded as unlisted stocks, which are bought and sold in over-the-counter (OTC) trading. Companies that do not allow shares to be publicly traded are called private corporations.