Trump Defies Supreme Court, Hikes Tariffs to 15% as Treasury Yields Tumble

U.S. Treasury yields dropped at the start of the week after the Supreme Court struck down a large portion of President Donald Trump's "reciprocal" tariffs in a 6-3 ruling on Friday. The court ruled that the International Emergency Economic Powers Act does not authorize the president to impose tariffs. The 10-year Treasury yield fell more than 5 basis points to 4.031%, the 30-year bond yield dropped over 2 basis points to 4.70%, and the 2-year note pulled back 4 basis points to 3.44%. Despite the ruling, Trump swiftly raised global tariffs from 10% to 15%, effective immediately, announcing further levies would follow. On Monday, he warned countries that "play games" would face even higher tariffs, deepening investor caution.