Why Mortgage Rates Change Even When Bank of England Base Rate Stays the Same

Why Mortgage Rates Change Even When the Bank of England Rate Stays the Same

By WIS Team

April 10, 2026

3 minutes read

TLDR

Mortgage rates do not always move in line with the Bank of England base rate. Lenders often price Fixed mortgages based on financial market expectations, swap rates, and funding costs, which means mortgage rates can change even when the base rate remains unchanged.

Key Point	Summary
Base rate	Set by the Bank of England and influences borrowing costs across the economy
Mortgage pricing	Determined by lenders based on funding costs, risk, and competition in the market
Swap rates	Financial market benchmarks that heavily influence fixed-rate mortgage pricing
Market expectations	Future interest rate expectations can cause lenders to adjust mortgage rates in advance
Inflation impact	Higher inflation often leads to higher interest rate expectations, affecting mortgage affordability

Understanding the Bank of England Base Rate

The Bank of England base rate influences borrowing costs across the economy. However, mortgage rates are not determined solely by this rate. Lenders also consider market expectations and funding costs when pricing mortgage products.

What Are SONIA Swap Rates?

SONIA swap rates are financial market interest rates derived from SONIA (the Sterling Overnight Index Average). They reflect the cost for banks to exchange fixed interest payments for floating payments linked to SONIA over a set period of time.

In the UK mortgage market, SONIA swap rates are widely used by lenders as a benchmark when pricing fixed-rate mortgages.

If swap rates increase, lenders may adjust mortgage pricing accordingly.

Why Mortgage Rates Can Change Without a Base Rate Move

Mortgage rates may change due to:

inflation expectations
global financial market movements
economic forecasts
funding costs for lenders

These factors may shift even when the Bank of England base rate remains unchanged.

Real Life Example

When the Bank of England reduced the base rate from 4% to 3.75%, several borrowers who had previously secured fixed-rate mortgages contacted us to ask whether their mortgage rates would fall as well.

At first glance, it might seem logical that fixed mortgage rates would decrease whenever the Bank of England cuts the base rate.

However, although the base rate had fallen, the SONIA swap rates and broader market conditions had not changed significantly.

As a result, borrowers noticed that fixed mortgage rates remained relatively stable despite the base rate reduction.

FAQs

1. Do mortgage rates always follow the Bank of England base rate?

No, they are also influenced by financial markets.

2. What are swap rates?

Financial indicators reflecting expectations of future interest rates.

3. Why do lenders change mortgage rates quickly?

To reflect changes in market funding costs.

4. Can mortgage rates fall even if the base rate stays the same?

Yes, if financial market expectations change.

5. Should borrowers monitor financial markets?

Understanding market trends may help borrowers plan mortgage decisions.

FCA Disclaimer

Your home may be repossessed if you do not keep up repayments on your mortgage.

This article is for general information only and does not constitute personalised financial advice.