A bond-market selloff tied to the Iran war has pushed key U.S. Treasury yields to their highest levels since January 2025, adding new pressure to mortgage borrowing costs nationwide. The effect has landed quickly in the housing market, where Freddie Mac reported a sharp weekly increase in the average 30-year fixed mortgage rate. For homebuyers and homeowners across the United States, the higher yields mean financing costs are rising even as affordability was already stretched.
Treasury yields climbed as the conflict fed inflation fears
The benchmark 10-year U.S. Treasury yield reached 4.687% on Tuesday, May 19, its highest level since January 2025, according to Reuters market reporting published May 21. Reuters also reported that the 30-year Treasury bond briefly touched 5.197%, its highest level since July 2007, during the same selloff. Those moves matter because the 10-year Treasury is a widely used benchmark for pricing consumer borrowing, including home loans.
Reuters said the selloff accelerated as investors reacted to concern that the Iran war would keep energy prices elevated and reinforce inflation pressures. Brent crude rose alongside yields during the period, and strategists told Reuters that the market was reassessing expectations for Federal Reserve policy. BMO Capital Markets strategist Vail Hartman told Reuters the market had been “breaking out higher” on yields as sentiment moved away from a rate-cut narrative.
By May 22, yields had eased somewhat as reports of possible peace-deal progress emerged, but Reuters said the earlier surge had already marked the highest 10-year level since January 2025. That left borrowing markets absorbing the effects of a rapid repricing in interest-rate expectations and geopolitical risk.
Freddie Mac said the average rate on a 30-year fixed-rate mortgage rose to 6.51% in the week reported May 21, up from 6.36% a week earlier, according to Reuters. Reuters described that as the highest level since August and the largest weekly jump in eight weeks. The increase followed the climb in the 10-year Treasury yield from around 4% in late February to more than 4.60% by late May, a move Reuters linked directly to inflation concerns tied to the war.
Earlier in the spring, Reuters reported on April 2 that the average 30-year fixed mortgage rate had already risen to 6.46%, the highest since early September. That report said the rate was up by nearly half a percentage point from just before the February 28 start of the Iran war. Freddie Mac’s historical survey archive shows mortgage rates remained elevated through much of 2025, underscoring how sensitive housing finance has been to swings in bond yields.
The national figures do not break out the impact by state or metro area, and Freddie Mac has not released state-level mortgage-rate data in its weekly survey. What is confirmed is that higher benchmark yields have translated into higher financing costs for borrowers across the U.S. housing market.
Reuters attributed the rise in yields primarily to inflation concerns tied to elevated energy prices during the conflict. On May 22, Reuters reported that the roughly three-month conflict had driven up energy prices and increased the odds that the Federal Reserve would maintain a hawkish policy stance. Brandywine Global portfolio manager Jack McIntyre told Reuters that inflation had already been running above the Fed’s target for years, making the environment difficult for Treasury yields even aside from the war.
That broader rate backdrop has practical consequences for buyers. Mortgage rates typically track the 10-year Treasury yield because investors use government bond yields to price long-term lending risk. When Treasury yields rise, lenders generally charge more for 30-year home loans to maintain returns and account for changing inflation expectations.
For households, that means higher monthly payments on new mortgages and less purchasing power for the same home price. Reuters noted that the spring increase in mortgage rates arrived during a key homebuying period, adding strain to a market where affordability was already constrained before the latest jump in yields.