Mortgage Rates Rise to 6.38% as Spread Widens (Despite Falling Treasury Yields)

The 30-year fixed mortgage rate averaged 6.38% for the week ending March 26, 2026, according to the Freddie Mac Primary Mortgage Market Survey. That is up from 6.22% the prior week, the second consecutive large weekly increase. The 10-Year Treasury yield actually fell 6 basis points during the same period, meaning the entire rate increase, and then some, came from a widening mortgage-Treasury spread that expanded from 183 to 205 basis points in a single week.

This Week's Numbers

12-Month Rate Trend

What Is Driving Rates

There was no FOMC meeting this week, and the 10-Year Treasury yield actually fell 6 basis points, from 4.39% to 4.33%. Under typical conditions, that decline would have pulled mortgage rates lower. Instead, the 30-year fixed rate climbed 16 basis points. The explanation is entirely in the mortgage-Treasury spread, which expanded from 183 to 205 basis points in a single week.

That 205-basis-point spread is 35 basis points above the long-run historical average of approximately 170 basis points. If the spread were sitting at its average with Treasury yields at 4.33%, the 30-year fixed rate would be approximately 6.03%, not 6.38%. The 35-basis-point premium above the historical norm represents the cost of Mortgage-Backed Securities (MBS) market dysfunction, not fundamental interest rate policy.

Several forces are likely driving the spread wider. The Federal Reserve continues to reduce its MBS holdings through quantitative tightening, removing a major buyer from the market. The March dot plot signaled fewer rate cuts than investors had expected, prompting a repricing of MBS duration risk. And broader market uncertainty around fiscal policy and tariff negotiations has pushed investors toward safer Treasuries and away from mortgage bonds, widening the gap between the two instruments.

This is the critical signal: rates rose for the wrong reason. When rates climb because Treasury yields rise, the path back down is straightforward. Treasuries fall, and mortgages follow. When rates climb because the spread widens, the correction depends on MBS market dynamics that are harder to predict and slower to resolve. For mortgage rates to reach Fannie Mae's forecast levels, both Treasury yields and the spread need to cooperate.

Where We Are in the Cycle

The 30-year fixed rate is 51 basis points below the 12-month high of 6.89%, recorded during the week of May 29, 2025, and 40 basis points above the 12-month low of 5.98% from late February. Year over year, rates are 27 basis points lower: 6.38% today versus 6.65% in March 2025.

Two consecutive weekly increases of 11 and 16 basis points have erased most of the gains from the February low. The steady decline that ran from May 2025 through February 2026 has reversed sharply. Fannie Mae's Q1 2026 forecast of 6.0% is now 38 basis points below the actual reading, and their 5.8% annual average projection is 58 basis points below where rates sit today. For those forecasts to hold, rates would need to fall substantially in the second half of the year.

What Borrowers Pay at Current Rates

Payment Impact

The table below shows how rate changes affect monthly principal and interest on a $320,000 loan (a $400,000 home with 20% down). These figures cover principal and interest only; actual closing costs and ongoing expenses add to the total.

What This Means for Borrowers

Buyers Under Contract

Spread-driven volatility makes the case for locking stronger than usual. When rates rise because of Treasury yields, the movement tends to be orderly and somewhat predictable. When the spread is the driver, rates can move sharply in either direction on no apparent catalyst. Borrowers under contract should consider securing a rate lock of 30 to 45 days rather than floating through the next several weeks. The April 28-29 FOMC meeting adds another uncertainty layer.

Buyers with Flexibility

Fannie Mae still forecasts the 30-year rate reaching 5.7% by Q4 2026. But that projection requires two things: continued Fed easing and spread normalization back toward 170 basis points. The Fed has not cut since December, and the spread has moved in the wrong direction. Buyers with timeline flexibility should watch the spread as closely as they watch Treasury yields. An adjustable-rate mortgage becomes relatively more attractive at wider spreads, because ARM pricing is less sensitive to MBS market conditions than 30-year fixed pricing.

Refinance Candidates

The jump from 5.98% to 6.38% in four weeks has narrowed the refinance window materially. Borrowers holding rates at 7.00% or above still have a clear benefit, but those near 6.75% should recalculate whether the savings justify closing costs. Fannie Mae projects the refinance share climbing to 41% of originations in 2026, up from 29% in 2025. That projection assumes rates resume their decline. At 6.38%, the surge in refinance volume is less likely to materialize on the timeline they forecast.

Rate Buydown Math

At current rates, one discount point costs $3,200 (1% of a $320,000 loan) and reduces the rate by approximately 0.25%. That buys $52 per month in savings, with a breakeven period of 62 months, or about 5.2 years. Buyers who plan to stay in the home beyond that horizon may find points worthwhile, particularly if they believe the spread will take time to normalize and rates will remain elevated longer than forecasters expect.

What to Watch

The mortgage-Treasury spread is the first variable to watch. Whether it normalizes from 205 basis points back toward the 170-basis-point historical average matters more for borrower costs right now than anything the Fed does with its overnight rate. A spread that compresses by 35 basis points would bring rates back below 6.10% at current Treasury levels, with no Fed action required.

The April 10 CPI release will shape Treasury yield direction. A cooler-than-expected print could revive rate cut expectations and pull yields lower. The April 28-29 FOMC meeting does not include updated projections, but the statement will signal whether the hawkish March stance holds. The June 16-17 FOMC includes the next dot plot and is the earliest realistic window for a rate cut. MortgageLoans.net will publish an updated rate analysis following the next PMMS release on April 3, 2026.

Key Takeaways

• The mortgage-Treasury spread widened from 183 to 205 basis points in one week, well above the historical average of 170 bps. This spread expansion, not Treasury yields or Fed policy, drove the entire rate increase.
• The 30-year fixed rate rose 16 basis points to 6.38% even as the 10-Year Treasury yield fell 6 basis points to 4.33%, a divergence that signals MBS market repricing rather than a shift in monetary policy.
• At the historical average spread, current Treasury yields would produce a 30-year rate of approximately 6.03%, not 6.38%. Borrowers are paying a 35-basis-point premium for spread dysfunction.
• Two consecutive weekly increases (+11, then +16 basis points) have erased most of the decline from the February low of 5.98%, pushing rates 40 basis points above that mark.
• Fannie Mae's Q1 forecast of 6.0% is now 38 bps below actual, and their 5.8% annual average is 58 bps below current rates. Both forecasts require significant second-half improvement.
• A $320,000 borrower at 6.38% pays $1,997 per month in principal and interest, $108 less than the 12-month high but $83 more than the late-February low.
• The next major catalysts are the April 10 CPI release, the April 28-29 FOMC meeting, and the June 16-17 FOMC with updated projections.