It was another shaky day on Wall Street as indexes rallied in the morning, bobbed up and down for much of the day, then sank in the last few minutes of trading. Energy companies dropped along with oil prices and technology companies also declined. On Wednesday: The Standard & Poor's 500 index skidded 13.48 points, or 0.5 percent, to 2,681.66. The Dow Jones industrial average shed 19.42 points, or 0.1 percent, to 24,893.35. The Nasdaq composite tumbled 63.90 points, or 0.9 percent, to 7,051.98. The Russell 2000 index of smaller-company stocks rose 0.80 points, or 0.1 percent, to 1,507.97. For the week: The S&P 500 is down 80.47 points, or 2.9 percent. The Dow is down 627.61 points, or 2.5 percent. The Nasdaq is down 188.