Wall Street’s main indexes opened down on Friday as banking heavyweights JPMorgan, Wells Fargo, and Citigroup kicked off the fourth-quarter earnings season with mixed results, while big technology companies extended losses after a bruising selloff. The Dow Jones Industrial Average fell 117.19 points, or 0.32 percent, at the open to 35,996.43. The S&P 500 opened lower by 21.04 points, or 0.45 percent, at 4,637.99, while the Nasdaq Composite dropped 98.79 points, or 0.67 percent, to 14,708.02 at the opening bell.