The interest rate set by the Fed, the federal funds rate, serves as a benchmark for all other rates. A change in the fed funds rate, the lending rate banks charge each other for the use of overnight funds, translates directly through to all other interest rates from Treasury bonds to mortgage loans. It also changes the dynamics of competition for investor dollars: when bonds yield 10 percent, they will attract more money away from stocks than when they only yield 5 percent.

The level of interest rates affects the economy. Higher interest rates tend to slow economic activity; lower interest rates stimulate economic activity. Either way, interest rates influence the sales environment. In the consumer sector, few homes or cars will be purchased when interest rates rise. Furthermore, interest rate costs are a significant factor for many businesses, particularly for companies with high debt loads or who have to finance high inventory levels. This interest cost has a direct impact on corporate profits. The bottom line is that higher interest rates are bearish for the financial markets, while lower interest rates are bullish.