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.

Risk is back on, and Pony AI (Nasdaq: PONY) is galloping ahead by over 27% today after rising as much as 30% in the session. At $7 per share, PONY stock is trading at volume of over 13 million shares compared with an average of 2 million shares trading hands,

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.