CME Group operates some of the world's largest futures and options exchanges, where traders buy and sell standardized contracts tied to interest rates, stock indices, commodities and currencies rather than the underlying assets themselves. As an exchange operator, CME earns transaction fees on every contract traded and additional fees for clearing those trades, a scale business where liquidity attracts more liquidity, since traders prefer markets where it's easy to get in and out of a position. The company owns some of the most heavily traded futures contracts in the world, including those tied to U.S. Treasury rates and major stock indices, giving it a durable position that's hard for new exchanges to challenge. CME's trading volumes, and therefore its revenue, tend to rise during periods of market volatility, when more traders and institutions are actively hedging or speculating on price moves.