President Trump is threatening 25% tariffs on Japan and South Korea after months of trade talks have yet to seal a deal. The S&P 500 turned lower in Monday afternoon trading, but investors know there's a good chance this won't be the final word.

The 25 percent duty threatened in the letters effectively matches the initial reciprocal tariffs Trump briefly imposed on the two countries in April.

US President Donald Trump has announced a 25% tariff on goods from Japan and South Korea, effective August 1. This decision was shared on his social media platform, Truth Social, where he posted letters sent to the leaders of these countries.