U.S. stock indexes nudged higher Friday after energy companies clawed back some of their sharp losses from earlier in the week. On Friday: The Standard & Poor’s 500 index rose 3.80 points, or 0.2 percent, to 2,438.30. The Dow Jones industrial average dipped 2.53 points, or less than 0.1 percent, to 21,394.76. The Nasdaq composite
