The S&P 500 and Nasdaq have both felt pressure as shares of major tech companies came under pressure Monday. Investors continue to keep a close eye on rising Treasury yields, which heighten worries about valuations, particularly for some of the market's most highly valued names.

The 10-year Treasury yield ( ^TNX) added to recent gains to touch a 14-month high, trading around 4.8% as US bonds sold off. Meanwhile, the dollar ( DX-Y.NYB) surged to a two-year high against major currency peers, with the UK pound ( GBPUSD=X ), in particular, coming under pressure.

Drops for Nvidia and other tech stocks are weighing on Wall Street Monday and keeping it in its weekslong rut. The S&P 500 was down 0.4% in morning trading, coming off its fourth losing week in the last five.

Drops for Nvidia and other Big Tech companies were offset by gains in health care, energy and other sectors, leaving U.S. stock indexes mixed. The S&P 500 wound up with a gain of 0.2% after spending most of the day lower.