Why Are Mortgage Rates Rising Before the Bank of England Changes BoE Rate?
The Bank of England's next interest rate decision is due on 17 September 2026.
For many homeowners and prospective buyers, that raises an obvious question:
If the BoE Rate is still 3.75%, why are some lenders increasing their mortgage rates?
The answer is that mortgage rates do not simply wait for the Bank of England to announce its next decision.
In fact, lenders and financial markets are constantly looking ahead. Fixed-rate mortgages are largely influenced by wholesale market rates, particularly swap rates, which can move well before the Bank of England actually changes BoE Rate.
And that is what borrowers are seeing now.
Bank of England's Rate and Mortgage Rates Are Not the Same Thing
Bank of England's Rate, commonly known as BoE Rate, is the interest rate set by the Bank of England's Monetary Policy Committee (MPC). It influences the wider cost of borrowing and saving across the UK.
The Bank has confirmed that its next rate-setting decision will take place on Thursday 17 September 2026.
But a lender pricing a fixed mortgage is much more complex.
There are several other factors involved, including the lender's funding costs, competition, risk, operating costs and, importantly, expectations about where interest rates may be in the future.
This is where swap rates come in.
What Are Swap Rates?
Think of swap rates as a window into what financial markets expect interest rates to look like over a particular period.
A two-year fixed mortgage is concerned with the cost of funding over roughly two years. A five-year fixed mortgage is concerned with the cost over roughly five years.
Lenders use interest-rate swaps and related wholesale market pricing to manage the risk of offering borrowers a fixed interest rate for that period.
Therefore, if markets suddenly expect interest rates to remain higher for longer, swap rates can rise.
And lenders can respond by increasing the rates on their fixed mortgage products.
This can happen even if the Bank of England has not changed BoE Rate at all.
The Bank of England itself explains that BoE Rate influences borrowing costs but is not the only factor determining the rates banks charge customers.
So Why Are Swap Rates Moving Now?
There are several factors currently affecting market expectations.
1. Inflation Remains a Concern
UK inflation was recently reported at 2.9%, above the Bank of England's 2% target.
Markets are therefore watching closely for evidence that inflation could remain persistent.
Higher-than-expected inflation can reduce expectations of near-term interest rate cuts and can even increase expectations of future rate rises.
That feeds into wholesale interest rates.
2. Energy Prices and Geopolitical Uncertainty
The ongoing conflict in the Middle East has pushed energy prices and inflation expectations higher.
Markets are particularly sensitive to oil prices because sustained increases in energy costs can feed into inflation across the economy. Recent market volatility has therefore pushed bond yields and swap rates higher.
3. Government Borrowing and Bond Yields
UK government borrowing also matters.
When gilt yields rise, this can put upward pressure on wholesale funding costs and swap rates.
Recent global bond-market selling has pushed UK yields significantly higher, with the five-year swap rate reaching its highest level in several years.
This matters because fixed mortgage pricing is closely linked to these wholesale market movements.
The Important Point: Markets Move Before the Bank of England
This is perhaps the most important concept for borrowers to understand.
The Bank of England reacts to economic data and sets BoE Rate. Financial markets are continuously pricing what they think the Bank of England will do next.
Markets do not wait until 17 September to start thinking about the September decision.
If investors believe inflation is likely to remain higher, they may anticipate that interest rates will stay higher for longer.
That expectation can push swap rates higher.
Lenders then review their mortgage pricing.
So a mortgage rate can rise before the Bank of England changes BoE Rate.
The recent movement demonstrates exactly this relationship. Moneyfacts data reported that major lenders including HSBC and NatWest had already increased mortgage rates in September as higher swap rates put pressure on lender margins.
Does This Mean the BoE Rate Will Definitely Rise on 17 September?
No.
This distinction is important.
At the time of writing, the Bank of England has not made its September decision.
A Reuters poll conducted in early September found that all 65 economists surveyed expected the Bank to leave BoE Rate unchanged at 3.75% at the 17 September meeting. However, financial markets have been pricing greater risks of future rate increases.
In other words, mortgage rates can move because expectations have changed, even if the actual BoE Rate has not.
And market expectations can change again.
What Does This Mean for Fixed-Rate Mortgage Borrowers?
If you are looking for a fixed-rate mortgage, the rate available to you today may not be the same rate available next week.
That does not mean rates will definitely continue rising. Markets can move in either direction.
But recent movements show why waiting for the Bank of England's announcement is not necessarily the same thing as waiting for mortgage rates to move.
By the time the MPC announces its decision, lenders may already have adjusted their mortgage pricing based on what markets were expecting.
The Bank of England's own analysis has previously shown how increases in market interest rates can feed through into mortgage rates, with OIS rates being an important benchmark for fixed-rate mortgage pricing.
What About Tracker and Variable-Rate Mortgages?
This is where the difference becomes particularly important.
Tracker Mortgages
A tracker mortgage is linked directly to BoE Rate, plus a specified margin.
So, if the BoE Rate stays unchanged, your tracker mortgage payment would not change simply because swap rates move.
If the BoE Rate increases, your monthly mortgage payments would increase, and if it falls, your payments will decrease.
Fixed-Rate Mortgages
Fixed-rate mortgages are different.
Their pricing is closely connected to wholesale market expectations and swap rates.
This is why two borrowers can see very different effects from the same market event.
Variable-Rate Mortgages
A variable-rate mortgage can be affected by changes to the lender's standard variable rate or other pricing decisions. As a result, monthly payments may change even when the mortgage is not directly linked to the Bank of England's rate.
The Takeaway for Borrowers
The simplest way to think about it is:
- BoE Base Rate tells us what the Bank of England is doing today.
- Swap rates reflect what financial markets think interest rates may look like in the future.
- Fixed mortgage rates are heavily influenced by those market expectations.
That is why mortgage pricing can move before the Bank of England's next announcement.
With the next MPC decision scheduled for 17 September, borrowers should not assume that mortgage rates will simply remain unchanged until then.
If you are approaching the end of your current fixed-rate mortgage, considering a new purchase or reviewing your mortgage options, it can be useful to understand what is driving mortgage pricing rather than focusing solely on the headline BoE Rate.
The mortgage market is forward-looking.
Your mortgage rate can be too.
What Should You Do If Mortgage Rates Are Changing?
If you are considering a mortgage, remortgage or new property purchase, it is important to look beyond the headline interest rate.
The overall cost of a mortgage can also depend on factors such as arrangement fees, valuation costs, early repayment charges, the length of the initial rate period and the lender's eligibility criteria.
Comparing the overall cost and suitability of different mortgage options can help you make a more informed decision.
If you are unsure how the current market could affect your mortgage, speak to a qualified mortgage adviser who can assess your circumstances and explain the options available to you.
Disclaimer: This article is provided for general information only and does not constitute mortgage, financial or legal advice. Mortgage eligibility, lending criteria, interest rates and product availability vary between lenders. Always seek professional advice before making financial decisions.
Your home may be repossessed if you do not keep up repayments on your mortgage.