The UK is experiencing its highest borrowing costs since 1998, with the government selling 30-year bonds at a yield of nearly 6%. This significant increase in Gilt yields is making UK bonds more attractive to investors, potentially diverting funds away from the stock market. For instance, a benchmark 30-year bond sale on September 8, 2026, saw a yield of 5.82% for £4 billion, marking the highest rate since the Debt Management Office was established.
This surge in borrowing costs is being driven by a global bond sell-off and concerns over inflation, especially after a resumption of conflict in the Middle East pushed up oil prices. Investors are also fretting about rising public debt, making them demand greater compensation for holding long-dated government debt. The UK 10-year Gilt yield reached 5.2% on September 8, 2026, compared to 4.8% for its US equivalent, according to FT data.
The rising Gilt yields pose a significant risk to UK equities, with some fund managers considering a bond market rout as the "most underappreciated downside risk" to stock markets. While equities have performed well, with the S&P 500 and FTSE 100 both up over 10% this year, a continued sharp rise in yields could make bonds competitive with or even outperform equities, particularly if the US 10-year Treasury yield breaches a psychological threshold like 5%. This could lead to a re-evaluation of UK stocks, which have historically been favored for their income-generating capabilities.
However, not all analysts are equally concerned. Some, like CJ Cowan of Quilter, note that current Gilt yields are simply returning to levels seen in 2003 and 2004, aligning with the Bank of England's interest rates. They argue that the yield curve is not particularly steep, suggesting that while there may be economic pain, it doesn't necessarily signal a market crisis. Yet, the consensus remains that the pace and volatility of yield increases are critical, and a disorderly sell-off could impact equities significantly. Aviva Investors, for example, is increasing its exposure to UK Gilts, betting that high yields will constrain government spending.
