The recent optimism on Wall Street dissipated early Thursday as companies continued to reassess their financial outlooks due to uncertainty over U.S. President Donald Trump's on-again-off-again tariff policies.

The S&P 500 plummeted 19% from its record high after President Trump announced the most severe tariffs the U.S. has seen in a century. In the short run, the 90-day pause on reciprocal tariffs makes for an uncertain business environment that will likely lead to more stock market volatility.