Why Mortgage Rates Are Rising Despite Unchanged Bank of England Base Rate
In a puzzling financial trend, mortgage rates in the UK have been climbing even as the Bank of England has maintained its base rate at 3.75%. To understand this phenomenon, one must delve into the world of swap rates and the broader economic impacts of geopolitical conflicts, such as the recent airstrikes on Iran by the US and Israel.
The Role of Swap Rates in Mortgage Pricing
Most mortgages in the UK are offered on a fixed interest rate, typically for two, three, or five years. Lenders fund these mortgages through a combination of customer savings and money borrowed on wholesale markets. This is where swap rates become crucial. Swaps are financial instruments used by banks to manage risks associated with interest rate changes. In a swap, one bank pays a fixed interest rate to another in exchange for a floating (variable) rate, effectively "swapping" the risk of potential rate increases.
Adam French, head of consumer finance at Moneyfacts, explains that lenders use swaps to convert variable-rate borrowings into fixed rates, thereby mitigating risk. Olly Cheng, senior financial planning director at Rathbones, adds that swaps allow parties to take on different types of risk—fixed or variable—based on their expectations and comfort levels.
Geopolitical Tensions and Economic Shocks
The recent airstrikes on Iran have triggered economic shocks globally, leading to stock market declines, rising petrol and heating oil prices, and warnings of increased costs for essentials like food and holidays. These developments influence interest rate expectations, which in turn affect mortgage rates. Before the conflict, the Bank of England was anticipated to cut rates twice this year due to falling inflation. However, the Middle East crisis has reset forecasts, with inflation now expected to rise, prompting the Bank to consider rate hikes to curb it.
Neal Hudson, a housing market analyst at BuiltPlace, notes that swap rates reflect risk, and current economic volatility has driven them higher. For instance, five-year swap rates jumped from 3.603% on March 2 to 4.03% recently, indicating market expectations of at least a 0.25 percentage point rise over the next five years.
Impact on Mortgage Deals and Lender Behavior
Cheng emphasizes that swap rates are the primary factor in mortgage pricing, though banks' profit margins and risk appetite also play roles. Hudson points out that lenders are cautious about offering overly competitive deals in such a volatile market, fearing exposure to sudden shifts. Additionally, concerns about future house price trajectories, if the war prolongs and squeezes living costs, make lenders wary of lending on properties that might lose value.
This volatility has led to mortgage deals being pulled and repriced at unprecedented speeds. French observes that the usual one-to-two-week lag in rate adjustments has vanished, with changes occurring much faster due to rapid rate shifts.
Historical Context and Future Outlook
Currently, the two-year swap rate remains below the peak seen after Liz Truss's mini-budget, when it soared to 5.75% despite a base rate of just 2.25%. As of Monday, it was just under 4%. If the conflict ends soon, swap rates and mortgage deals could trend downward. However, if tensions persist, consumers should brace for higher mortgage costs.
In summary, the rise in mortgage rates despite a stable Bank of England base rate is driven by swap rate increases fueled by geopolitical risks and economic uncertainty. Understanding these mechanisms is key for homeowners and prospective buyers navigating the housing market.



