S&P, Nasdaq end lower as Nvidia drags the tech sector for second day ReutersStock Market Today: Dow, S&P Live Updates for June 21 BloombergDow Jones Futures: S&P 500, Nasdaq Retreat As AI Stocks Skid; Time To Sell Nvidia? Investor’s Business DailyNearly $6 trillion in options due to expire during Friday’s record-breaking ‘triple witching’ MarketWatchS&P 500 closes lower Friday as Nvidia falters, Dow posts best week since May: Live updates CNBC