If you bought a house six weeks ago, the same loan today costs about $215 more a month. That’s not because the Federal Reserve did anything. The Fed has held its benchmark rate flat all year. It’s because long-dated Treasury yields jumped when the first U.S. and Iranian shells were exchanged across the Persian Gulf, and mortgage rates follow long Treasuries.

This is one of the more underappreciated facts of the rate cycle we’re in. The Fed is the headline. The 10-year is the bill.

What the numbers say

On April 1, the average 30-year fixed-rate mortgage was 5.81%, according to Mortgage News Daily’s daily survey. By Wednesday’s close, it was 6.22%. The CPI reading for March came in at 3.3% year-over-year — up from 2.4% in February — and the bond market read that as evidence the Iran-related oil shock was going to bleed into core inflation faster than anyone wanted to assume.

Apply both moves to a $400,000 loan and the monthly payment goes from roughly $2,346 to $2,461. Over the life of the loan that’s about $41,000 in additional interest, before any refinance.

Add to this the small but real shift in lender behavior: at least three large mortgage banks have tightened debt-to-income overlay limits in the past two weeks, and FHA/VA spreads to conventional have widened by about 12 basis points. None of this is dramatic. It is, in the aggregate, real.

What I’d actually do

If you’re closing in the next 30 days, lock the rate today. The case for waiting depends on the Fed cutting, and the Fed is not going to cut into a bond-market-driven inflation surge.

If you’re closing in 60–90 days, lock-and-shop is worth the float-down fee. Most major lenders charge between 12 and 35 basis points for the option, and the option is what you’re paying for — not a guess about which way rates go.

If you’re not buying — if you’re just refinancing what you have — wait. The two scenarios where rates fall meaningfully from here are a Gulf de-escalation or a real labor-market crack, and the second one is the kind of thing you don’t want to refinance into.

The Fed is not your problem this month. The strait is.