U.S. Stocks Open With Sharp Gains; Dow Jumps 187 Points

U.S. stocks opened sharply higher Friday, boosted by Federal Reserve Chairwoman Janet Yellen's signal late Thursday that the economy is strengthening and an interest-rate hike is likely before the end of the year. A revision to the second-quarter gross domestic product also showed the economy grew faster than first estimated. The main indexes were on track to finish the week roughly where they started. The S&P 500 opened 16 points, or 0.8%, higher at 1,948. The Dow Jones Industrial Average jumped 190 points, or 1.2%, to 16,387. The Nasdaq Composite began the day up 44 points, or 1%, at 4,779.