Mortgage rates ticked higher this week as renewed Middle East tensions pushed investors toward safer assets like Treasury bonds. When bond yields rise, mortgage rates follow suit, since lenders price mortgages based on the 10-year Treasury yield.

The uptick puts pressure on home buyers already dealing with elevated housing costs. Even a quarter-point increase matters. A borrower with a $400,000 loan sees monthly payments jump roughly $75 for every 0.25 percent rate increase. Over the life of a 30-year mortgage, that compounds to thousands of dollars in extra interest.

Geopolitical events like Middle East conflicts typically boost demand for Treasuries, which investors view as a safe haven during uncertainty. This increased demand pushes yields down initially, but when the market reprices risk, yields climb back up. Mortgage lenders adjust their rates accordingly within hours or days.

For prospective home buyers, the timing stings. Rates have remained stubbornly elevated throughout 2024, hovering in the upper 6 percent to low 7 percent range depending on credit score and loan terms. Today's increase adds another barrier to affordability in an already expensive market.

Refinancers face a tougher picture. If you locked in a rate below 6.5 percent last year, refinancing at current rates makes less financial sense. Most homeowners need at least a 0.5 to 1 percent drop to justify paying closing costs again.

The takeaway for shoppers: rate locks matter more than ever. Once you secure a rate quote from your lender, lock it in immediately. Most lenders offer 30-day to 60-day lock periods free of charge. Don't let rate volatility catch you off guard after you've found your home.

Monitor the 10-year Treasury yield if you want to predict mortgage rate direction.