Stocks lost ground Monday, but showed resilience by ending well off the day’s worst levels. The Nasdaq slipped just 0.1% after sliding 1.1% in the opening minutes. It briefly touched positive territory. The S&P 500 pared a 0.9% loss to 0.3%. Both of the major indexes closed above their 50-day moving averages, the latter by just a hair. The indexes started slipping below that line last week, although they closed below it just on Thursday.