Investors are wary about worrisome market signs, after a steep U.S. stocks selloff that has wiped out more than $4 trillion in value and all of the gains notched following President Donald Trump's election. Among the signs are technical signals such as the S&P 500 on Monday closing below a crucial trend line, a key measure of the market's internals weakening, a concerning pattern in volatility futures contracts, rising cash levels among investors and de-leveraging by hedge funds away from equities. U.S. equities experienced a punishing drop this week, with the S&P 500 briefly falling into correction territory on Tuesday as uncertainty over Trump's tariffs exacerbated worries about economic growth.