By Mari Hansen When stocks decline, bonds rise. This is a rule that most investors learn early and remember throughout their entire financial lives. It is the cornerstone of the diversified portfolio, the reasoning behind the 60/40 allocation that has been the standard setting for cautious investing for decades, and the reason why millions of investors in retirement accounts, ISAs, and pension funds get a decent night’s sleep even during a difficult month for the equity markets. The rule isn’t entirely incorrect. However, it has a prerequisite that textbooks frequently overlook: it only applies when markets are declining for the proper reasons. Bonds don’t offer refuge when markets decline due to inflation. They also fall.
In 2026, that condition has abruptly and inconveniently returned. Energy prices increased as a result of the Middle East conflict that disrupted the flow of oil through the Strait of Hormuz. Rising energy prices have a very specific effect on financial markets: they raise expectations for inflation, which in turn raises expectations for yields, which in turn drives down bond prices. By late March, UK 10-year gilt yields had increased from 4.3% in late February to 4.9%. That may seem like a minor change, but keep in mind that bond prices are inversely correlated with yields, and a move of that magnitude corresponds to a monthly price drop of about 5% for 10-year bonds. Gilts were losing value for investors who had moved into them in anticipation of protection from equity volatility. It wasn’t a hedge.
Key information — bond market failure & 2026 crisis
| Core problem | Bonds have failed to provide their traditional safe-haven protection during the 2026 equity selloff — because the shock originated from rising energy prices rather than a demand-side recession |
| Trigger event | Middle East conflict disrupting oil supply through the Strait of Hormuz — driving energy prices sharply higher and reigniting inflation fears across global markets |
| UK 10-year gilt yields | Rose from 4.3% in late February 2026 to 4.9% in late March — a significant move that pushed bond prices down roughly 5% over the same period |
| Two-year yield shift | Two-year UK gilt yields rose by nearly one full percentage point — reversing what had been an 80% market-priced expectation of a Bank of England rate cut to a 50% chance of a rate hike |
| Bond portfolio losses | Diversified UK gilts funds lost between 2% and 5% since end of February 2026 — investment grade corporate bond portfolios dropped approximately 3.5% over the same period |
| Why bond prices fell | When inflation expectations rise, central banks may issue new debt at higher yields — making existing lower-yield bonds less attractive and causing their market prices to decline |
| Inflation impact illustration | If inflation averages 5% over 20 years, £1,000 today would be worth approximately £375 in real terms — demonstrating why rising inflation is fundamentally damaging to fixed-income returns |
| Central bank dilemma | Bank of England policymakers have warned that aggressively hiking rates into an energy shock could seriously harm economic growth — creating a difficult balancing act between fighting inflation and avoiding recession |
| Oil market signal | The oil market entered deep contango after the conflict began — meaning futures prices imply oil will be cheaper in coming months, suggesting markets view the supply disruption as temporary |
| Historical parallel | The breakdown of the stock-bond negative correlation mirrors early April 2025 when U.S. long-term bonds also failed to offset equity losses during tariff-driven market stress |
The noise of market commentary obscures the mechanism, which makes it worthwhile to comprehend. It is anticipated that governments and central banks will raise interest rates in response to rising inflation expectations. New debt is issued at higher yields due to higher rates. The prices of current lower-yielding bonds decline until the yield differential closes because better-yielding new bonds make them less appealing.
It doesn’t care that investors purchased gilts especially to feel secure; it’s a completely logical process. The possibility that the Bank of England may need to raise rates rather than lower them is what the market is currently pricing while keeping an eye on the Strait of Hormuz and calculating how many days the supply disruption will last. Markets were pricing an 80% chance of a rate cut at future meetings just four weeks ago. There is now a 50% chance of a rate increase. That is a big change. Because of events occurring thousands of miles away from Threadneedle Street, the entire direction of monetary policy is moving quickly in the opposite direction.
The market for corporate bonds has not been exempt. Diversified investment grade portfolios have decreased by about 3.5% since the end of February as UK investment grade yields, the highest-quality segment of the corporate debt market, increased by about half a percentage point to 5.4%. Because corporate bonds are frequently viewed as a middle ground—more return than gilts, less risk than equities—this is noteworthy. They have not provided either trait in a helpful manner during this specific shock. The portfolio of stocks has declined. The portfolio of bonds has decreased. In terms of both components, the balanced allocation that was meant to balance things out has resulted in a portfolio that is just smaller than it was.
The post-pandemic era, which resulted in a nearly identical dynamic, is difficult to ignore. Bonds had one of the worst years in modern financial history when central banks started aggressively raising rates in 2022 to combat rising inflation. They fell concurrently with equities and provided none of the cushion that traditional portfolio theory had promised. The stock-bond negative correlation, which is the mathematical relationship that makes diversification work, is not a law of nature. This was the lesson that some investors learned from that episode, while many others did not. It is true in deflationary, demand-driven recessions. When shocks cause inflation, it breaks. By definition, energy crises cause inflation. According to one analyst, they function similarly to an increase in consumer taxes, decreasing overall economic spending while simultaneously driving up prices.
Interestingly, the bond market is currently reflecting a less optimistic signal than the oil market itself. Since the conflict started, futures prices have been in a deep contango, which means that the market is pricing oil to be less expensive in the coming months than it is now. This suggests that traders think the supply disruption is only temporary. That opinion is supported by the fact that US-Iranian negotiations seem to be gaining some momentum. Bond prices would partially recover their losses, yields would probably drop, and inflation expectations would ease if the conflict is resolved swiftly and energy prices start to decline. While acknowledging that the range of outcomes surrounding it is wider than anyone would prefer, most economists treat that scenario as the base case.
How long the supply disruption lasts and whether the inflationary impulse becomes embedded enough to compel central bank action are still genuinely unknown. Observing this in real time makes it evident that the bond-safety relationship is more conditional than most investment advice recognizes. Until the source of danger is the one thing bonds are unable to protect against, the safe haven is effective. And that source came with a price tag for oil in 2026.