The yield on the 10-year Treasury note rose above 1.55% after Mr. Powell’s interview—its highest level since before the pandemic—up from 1.46% earlier Thursday and 0.92% at the beginning of the year. Such rates influence many consumer and business borrowing costs. Following the run-up in Treasury yields in recent weeks, the average rate on a 30-year fixed-rate mortgage has risen above 3% for the first time since July, Freddie Mac said Thursday. That has started to weigh on applications to buy or refinance homes.