Investors are looking for signs the selling in the U.S. stock market may have reached a crescendo, but say that the check marks are not yet all ticked and there is room for further pain. President Donald Trump's announcement of sweeping tariffs on Wednesday extended U.S. stocks' selloff this year with the S&P 500 down 12% from its February record high and the tech-heavy Nasdaq index down 18% - close to being in a bear market. "We're definitely not at 'get me out!' levels," Steve Sosnick, chief strategist at Interactive Brokers, said.