The Chicago Board Options Exchange (CBOE), located at 400 South LaSalle Street in Chicago, is the largest U.S. options exchange with annual trading volume that hovered around one billion contracts at the end of 2007. CBOE offers options on over 2,200 companies, 22 stock indices, and 140 exchange-traded funds (ETFs).The Chicago Board of Trade established the Chicago Board Options Exchange in 1973. The first exchange to list standardized, exchange- traded stock options began its first day of trading on April 26, 1973, in a celebration of the 125th birthday of the Chicago Board of Trade.The CBOE is regulated by the Securities and Exchange Commission.