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.

President Donald Trump told Japan and South Korea the U.S. has set 25% tariffs on their goods, in the first of several trade moves expected to be announced over the next 48 hours. He will also issue an executive order that will extend the previous July 9 deadline for all trade deals to Aug.

President Trump posted letters to Japanese and South Korean leaders on social media, informing them he plans to impose 25% tariffs on their goods. He has said more letters to leaders will be coming.