The stock market stumbled to its biggest loss since June as traders worried that interest rates may finally be heading higher, the AP reports. Stocks that had the most to lose from higher rates suffered the most in the sell-off Friday. Utilities and phone stocks, which investors have sought out this year for their high dividends, fell far more than the rest of the market. AT&T slumped 3.6%. Energy companies, which have also gained a lot this year, took a drubbing as the price of crude oil slumped. Diamond Offshore Drilling dropped 10%. The Dow Jones industrial average lost 394 points, or 2.1%, to 18,085. The Standard & Poor's 500 index shed 53 points, or 2.5%, to 2,127. The Nasdaq composite fell 133 points, or 2.5%, to 5,125.