Market data is usually defined as prices for investments which trade on an exchange, such as stock prices from the New York Stock Exchange (NYSE) or futures prices from the Chicago Board of Trade. However, there are trillions of dollars worth of instruments that trade over the counter (OTC), which means they are traded between parties via perhaps simply a phone call backed up by a written agreement. There are many sources of market data online, and our hope is that this page will become an exhaustive list of data from sources around the globe in all markets.