The Dow Jones industrial average continued its march upward Monday, opening at a record high that tops last week's milestone of 21,391.97, CNBC reported.
The S&P 500 opened up 0.4 percent, leaving it just below a record of its own. And the Nasdaq composite rose as well, nearly 1 percent.
"I don't know where the optimism is coming from. That's not to say we should be negative. I just don't see any reason for excessive optimism or pessimism right now," said Randy Frederick, vice president of trading and derivatives at Charles Schwab.
Technology stocks were bouncing back from a rough week, with Facebook, Amazon, Apple, Netflix and Google-parent Alphabet all up about 1 percent in early trading.