are presumed to be among the first to be influenced by changes in economic conditions. As such, it serves as one early indication of impending changes in business activity." Commodity index fund A commodity index fund is a fund whose assets are invested in financial instruments based on or linked to a commodity index. In just about every case the index is in fact a Commodity Futures Index. The first such index was the Dow Jones Commodity Index, which began in 1933. The first practically investable commodity futures index was the Goldman Sachs Commodity Index, created in 1991, and known as the "GSCI". The next was the Dow Jones AIG Commodity Index. It differed from the GSCI primarily in the weights allocated to each commodity. The DJ AIG had mechanisms to periodically limit the weight of any one commodity and to remove commodities whose weights became too small. After AIG's financial problems in 2008 the Index rights were sold to UBS and it is now known as the DJUBS index. Other commodity indices include the Reuters / CRB index (which is the old CRB Index as re-structured in 2005) and the Rogers Index. Cash commodity Cash commodities or "actuals" refer to the physical goods—e.g., wheat, corn, soybeans, crude oil, gold, silver—that someone is buying/selling/trading as distinguished from derivatives. Call options In a call option counterparties enter into a financial contract option where the buyer purchases the right but not the obligation to buy an agreed quantity of a particular commodity or financial instrument (the underlying) from the seller of the option at a certain time (the expiration date) for a certain price (the strike price). The seller (or "writer") is obligated to sell the commodity or financial instrument should the buyer so decide. The buyer pays a fee (called a premium) for this right. Electronic commodities trading In traditional stock market exchanges such as the New York Stock Exchange (NYSE), most trading activity took place in the trading pits in face-to-face interactions between brokers and dealers in open outcry trading. In 1992 the Financial Information eXchange (FIX) protocol was introduced, allowing international real-time exchange of information regarding market transactions. The U.S. Securities and Exchange Commission ordered U.S. stock markets to convert from the fractional system to a decimal system by April 2001. Metrification, conversion from the imperial system of measurement to the metrical, increased throughout the 20th century. Eventually FIX-compliant