The Dow Jones industrial index fell 0.5 percent and the broad S&P 500 index declined 0.1 percent, while the technology-heavy Nasdaq composite index rose 0.4 percent.
Many investors fear that President Donald Trump's high tariffs, which came into force on Thursday, will harm the US economy – especially in light of last week's unexpectedly weak labor market statistics.
A heavy burden was the pharmaceutical company Eli Lilly, which plummeted over 14 percent, despite the company reporting higher profits than expected during the previous quarter. The market instead focused on disappointing results from a study of a new weight loss preparation, where several common side effects were noted.
Among the winners was the company behind the language app Duolingo. The stock soared 13.8 percent after the company's interim report far exceeded analysts' forecasts – sales increased by 46 percent compared to the same period last year.
