U.S. markets reversed course yesterday (September 23, local time), with all three major indices closing lower. The trigger was a sharp spike in Treasury yields. The U.S. 10-year yield surged to 5.13% , its highest level since 2007, marking a significant move in the fixed-income market. The Dow Jones, S&P 500, and Nasdaq Composite each gave back gains, erasing bullish momentum from the day before. The contrast was stark. Just one day earlier, on September 22, the Nasdaq closed at a record high following reports of a planned U.S.-Iran diplomatic meeting. That optimism evaporated overnight. Today, a U.S.-China summit is scheduled in Washington. The Korean market finds itself caught between these two pivotal geopolitical events. September 23 U.S. market heat map (S&P 500) · Green=gainers / Red=decliners (Finviz convention) Why Did All Three Major Indices Fall? The Dow Jones Industrial Average closed at 51,511.59 on September 23, down 352.10 points or 0.7% . The S...