An exchange-traded fund (ETF) is an investment fund traded on stock exchanges, much like stocks. An ETF holds assets such as stocks, commodities, or bonds, and trades close to its net asset value over the course of the trading day. Most ETFs track an index, such as the S&P 500 or MSCI EAFE. ETFs may be attractive as investments because of their low costs, tax efficiency, and stock-like features. ETFs are the most popular type of exchange-traded product.^{[citation needed]}

Only so-called authorized participants (typically, large institutional investors) actually buy or sell shares of an ETF directly from or to the fund manager, and then only in creation units, which are large blocks of tens of thousands of ETF shares, usually exchanged in-kind with baskets of the underlying securities. Authorized participants may wish to invest in the ETF shares for the long-term, but usually act as market makers on the open market, using their ability to exchange creation units with their underlying securities to provide liquidity of the ETF shares and help ensure that their intraday market price approximates to the net asset value of the underlying assets. Other investors, such as individuals using a retail broker, trade ETF shares on this secondary market.

A futures exchange or futures market is a central financial exchange where people can trade standardized futures contracts; that is, a contract to buy specific quantities of a commodity or financial instrument at a specified price with delivery set at a specified time in the future. These types of contracts fall into the category of derivatives. Such instruments are priced according to the movement of the underlying asset (stock, physical commodity, index, etc.). The aforementioned category is named "derivatives" because the value of these instruments is derived from another asset class.

One of the earliest written records of futures trading is in Aristotle's book Politics. He tells the story of Thales, a poor philosopher from Miletus who developed a "financial device, which involves a principle of universal application". Thales used his skill in forecasting and predicted that the olive harvest would be exceptionally good the next autumn. Confident in his prediction, he made agreements with local olive-press owners to deposit his money with them to guarantee him exclusive use of their olive presses when the harvest was ready. Thales successfully negotiated low prices because the harvest was in the future and no one knew whether the harvest would be plentiful or pathetic and because the olive-press owners were willing to hedge against the possibility of a poor yield. When the harvest-time came, and a sharp increase in demand for the use of the olive presses outstripped supply, he sold his future use contracts of the olive presses at a rate of his choosing, and made a large quantity of money. It should be noted, however, that this is a very loose example of futures trading and, in fact, more closely resembles an Option contract, given that Thales was not obliged to use the olive presses if the yield was poor.