Using examples from financial markets, this note examines links among market prices, stated interest rates, and compounding assumptions. The note emphasizes how interest rates are expressions of market prices, and pays particular attention to the role of compounding assumptions. Market prices are converted into stated interest rates for different compounding assumptions. Guidance is offered on how to make intelligent comparisons across markets that use different compounding conventions. The note is useful as background for the study of a wide array of pricing issues in fixed-income and options markets. See also "Interest Rate Derivatives" (UVA-F-1431).