U.S. stocks are drifting in mixed trading as they near the end of another roller-coaster week. The S&P 500 edged down by 0.1% Friday, as nearly three out of every four stocks were falling within the index.

Wall Street stocks advanced on Wednesday on revived hopes for progress in the U.S.-China trade dispute and as President Donald Trump soothed fears the Federal Reserve could lose its autonomy with reassurances that he has "no intention of firing" Fed Chair Jerome Powell.