UK mortgage rates rise as bond market turmoil lifts swap rates to three-year high

UK homeowners face an imminent increase in mortgage costs as global bond market instability drives swap rates to their highest level in three years. This shift is primarily attributed to rising inflation expectations triggered by a surge in oil prices following recent military exchanges between the United States and Iran. The resulting sell-off in government debt has pushed up yields, forcing lenders to reassess their pricing structures for new and existing residential and buy-to-let borrowers.

The five-year swap rate, a key benchmark used by banks to price fixed-term mortgages, climbed above 4.52 percent this week. This marks the highest point since October 2023. Coventry Building Society has already responded to these market conditions by becoming the first mainstream lender to raise rates across its entire fixed-rate mortgage portfolio. Although the acute volatility in bond markets showed signs of easing on Thursday, the underlying pressure on borrowing costs remains significant. The rise in gilt yields has directly increased the cost of interbank lending, which in turn elevates the interest rates charged to consumers.

The escalation in geopolitical tensions has been a central driver of the market reaction. The exchange of fire between the US and Iran for the first time in a month has led to a sharp increase in oil prices, fueling fears of persistent inflation. Investors have responded by selling bonds, which increases their yield. The impact on UK government bonds has been particularly pronounced compared to other nations. This environment has prompted the Bank of England’s chief economist, Huw Pill, to argue for a more proactive approach to monetary policy. Speaking in Edinburgh, Pill stated that the central bank cannot wait for uncertainties to resolve themselves before acting. He suggested that acting clearly and promptly would cut through the noise of the current uncertain environment, thereby bolstering the clarity and effectiveness of policy choices. Pill was one of three members of the monetary policy committee who advocated for a rate rise in July, though they were outvoted at the time.

Market analysts suggest that the current trajectory is likely to result in higher interest rates for credit cards, mortgages, and auto loans. Russ Mould, investment director at AJ Bell, noted that lenders will seek to preserve loan book margins and manage risk as bond yields rise. The sustained high cost of government borrowing also poses a challenge for the new prime minister, Andy Burnham, who is attempting to ease cost of living pressures. Burnham sought to calm volatile markets during his first appearance at prime minister’s questions, promising that decisions for the autumn budget would be grounded in fiscal responsibility. This statement came as the yield on UK 10-year government debt hit its highest level since 2008 for a second day, before retreating slightly following a drop in oil prices. On Thursday, Brent crude, the global oil benchmark, dipped 0.6 percent to 95 dollars a barrel.

Tom Simpson, managing director of homes at Yorkshire Building Society, indicated that swap rates are now 0.7 percent higher than they were a year ago. He noted that while there was significant volatility in March at the start of the conflict, the recent increase of 0.1 percentage point over the past week is lower than the 0.5 percentage point rise seen in the ten days following the initial airstrikes on Tehran. Simpson advised consumers concerned about these changes to consult independent mortgage advisers. He observed that market movements often pull forward demand, as borrowers attempt to lock in current rates. Despite the rising benchmarks, fixed-year mortgage rates remained unchanged on Thursday according to Moneyfacts data. The average two-year fix stands at 5.59 percent, while a typical five-year fixed deal costs 5.63 percent. The broader context includes increased competition for capital from corporate debt issuance by technology companies funding artificial intelligence infrastructure, further complicating the bond market landscape.