Bond market turbulence: Why mortgage rates can rise even when Bank Rate stays still
Mortgage borrowers received an important reminder in September that Bank Rate is only one part of the interest rate story. UK government borrowing costs rose sharply at the beginning of the month, pushing wholesale market rates higher and prompting lenders to increase mortgage pricing. Then, on 17 September, the Bank of England kept Bank Rate at 3.75%, but three of the nine Monetary Policy Committee members voted for an immediate increase to 4%.
The Bank also said UK inflation had risen to 3.1% in August and warned that inflation risks had moved further to the upside. Its September decision is here: https://www.bankofengland.co.uk/monetary-policy-summary-and-minutes/2026/september-2026
For buyers and remortgagers, the message is straightforward. A Bank Rate hold does not guarantee stable mortgage rates, because fixed rate pricing is influenced by financial markets that can move well before the Bank changes its headline rate.
Why gilt yields matter
Gilts are bonds issued by the UK government. Their yields reflect the return investors demand for lending money to the government for different periods.
At the beginning of September, the benchmark 10 year gilt yield briefly reached 5.294%, its highest level since August 2007. Five year gilt yields also reached their highest level since September 2023 as concerns about energy prices, inflation and government borrowing combined with turbulence in global bond markets. Reuters reported on those moves here: https://www.reuters.com/business/british-government-bond-yields-hit-fresh-18-year-high-oil-prices-rise-2026-09-02/
Fixed mortgages are not priced directly from government bond yields. Swap rates are usually a more immediate influence. These represent the market cost of exchanging interest payments over different periods and are closely tied to expectations for future interest rates.
When markets become more concerned that inflation will remain high, expectations for future rates can rise. Swap rates then tend to move higher, increasing the cost to lenders of offering fixed mortgages.
The Bank Rate hold has not removed that pressure
The September MPC decision reinforced that point. Although six members voted to keep Bank Rate at 3.75%, three wanted to raise it to 4%.
The Bank also said short term overnight index swap rates had risen further since July and that increases had passed through quickly into borrowing costs. Its minutes noted that quoted two year fixed mortgage rates were around 0.95 percentage points higher than before the latest Middle East conflict began.
That means borrowers should not interpret the September hold as a signal that mortgage pricing is about to settle down. The Bank has explicitly said that the inflation outlook has become more uncertain and that it remains prepared to act if necessary.
Mortgage lenders have already been repricing
The effect has been visible in mortgage rates. Moneyfacts said on 16 September that major lenders including NatWest, Santander, HSBC and Lloyds Bank had increased rates for the second time since the beginning of the month.
By 17 September, Moneyfacts showed an average two year fixed mortgage rate of 5.83% and an average five year rate of 5.87%. Its live fixed mortgage data is here: https://moneyfactscompare.co.uk/mortgages/fixed-rate-mortgages/
Those are market averages, not necessarily the rates an individual borrower will pay, and considerably cheaper deals remain available for some borrowers. But the broader direction illustrates why waiting for a Bank of England announcement before reviewing your options can be misleading.
One change could ease some bond market pressure
There was also an important announcement alongside the September rate decision. The Bank changed the way it plans to unwind the government bonds accumulated through quantitative easing.
It will now reduce its remaining monetary policy gilt holdings through a multi year plan, including £20 billion of annual active sales, while pausing its existing APF auctions for now. Long dated gilts rallied after the announcement, with the 30 year yield falling noticeably on the day. Reuters reported on the reaction here: https://www.reuters.com/business/investors-cheer-boe-move-pause-gilt-sales-driving-bond-rally-2026-09-17/
That could remove one source of pressure from the gilt market. It does not, however, remove the inflation risks currently influencing shorter term interest rate expectations and mortgage pricing.
What this means if you are buying
If you are buying, the single most important factor remains when you find the right property. Trying to perfectly time bond markets or the next Bank of England decision can become a distraction from the bigger question of whether the property and mortgage are right for you.
Once you have found somewhere, preparation becomes important. Have your agreement in principle current, your documents ready, and a realistic idea of the monthly payment you can comfortably afford.
If a suitable mortgage is available, delaying purely because Bank Rate might eventually fall carries a risk. Fixed rates can move in either direction before the Bank makes its next decision.
What this means if you are remortgaging
For remortgagers, starting early can be particularly useful. Reviewing your options several months before your current deal ends gives you more time to compare products and potentially secure a suitable option before further repricing.
The next Bank Rate decision is due on 5 November. But the September meeting demonstrates why borrowers should not treat that date as the only thing that matters. Wholesale markets will continue to react to inflation, energy prices and economic data in the meantime.
Practical takeaways
Bank Rate matters, but it is not a mortgage price list. Gilt yields, swap rates, inflation expectations and lender funding costs can all move fixed mortgage pricing while Bank Rate remains unchanged.
The September decision has arguably strengthened that message. The Bank held rates, but three policymakers wanted an increase and the inflation risks have become more pronounced.
For buyers, finding the right property and making sure the mortgage is affordable should remain the priority. For remortgagers, starting early can reduce the risk of being caught by another round of lender repricing. Altura Mortgage Finance can help you compare current options and decide when it makes sense to act.
Your home or property may be repossessed if you do not keep up repayments on your mortgage or any other debt secured on it. Think carefully before securing other debts against your home. The guidance and/or advice contained within the website is subject to the UK regulatory regime and is therefore primarily targeted at customers in the UK. Altura Mortgage Finance Limited is authorised and regulated by the Financial Conduct Authority. Firm Registration No: 827849 www.fsa.gov.uk/register/home.
