Sellers took center stage early Wednesday as news of a possible China trade barrier for Nvidia put a chill on tech firms specializing in artificial intelligence, and the markets in general.

The stock is one of just 74 in the S&P 500 that is trading above its 50-day moving average, which is also above its 200-day ...

Flashing "sell" signals mean traders should bet on a decline in the S&P 500, says Longview Economics. In a new note sent Wednesday, the U.K.-based research consultancy said its short term models that ...