The Dow ended lower Monday but the S&P 500 and the Nasdaq Composite both booked record closes, supported by gains in big-capitalization technology companies and communication services. The Dow Jones Industrial Average, weighed by a decline in Boeing Co. BA, -3.39%, ended solidly lower. The blue-chip index closed down 0.4% to around 34,281, on a preliminary basis. Meanwhile, the S&P 500 index SPX, +0.23% logged its 32nd record finish of 2021, up 0.2% to finish above 4,290, while the Nasdaq Composite COMP, +0.98% charged up by 1% to 14,500 and marked its 18th closing record of the year. The Nasdaq Composite's moves were led by gains in Amazon.com Inc. [: AMZN], Nvidia Corp. NVDA, +5.01% and Tesla Inc. TSLA, +2.51%.