SynopsisThe relationship between bond yields and the market is not mechanical. A rise of 20 basis points in the US Treasury yield does not mean every company suddenly pays 20 basis points more or that equity valuations fall by a predictable amount. That is well understood. But what does this have to do with the Gulf war and the surge in oil prices?
When the US-Iran war started in the Gulf region, the initial fear was a familiar one: Oil shock. And countries like India that are heavily dependent on imported crude were expected to take the biggest hit. That is how things have played out in the past, and the markets reacted accordingly.
But this time the shock has moved to a new sphere. Over the past month, a bigger warning has come from the global bond market. Yields have risen sharply across several developed economies, from the US and the UK to Japan. Japan is, in fact, the most striking example. It is an economy that has lived with near-zero and even negative interest rates for years. And now long-term bond yields are near levels not seen in about three decades.
So, this time, the shock is becoming harder to contain. Oil still starts the process, but the transmission mechanism now runs through government bond markets, which means the eventual cost can reach countries far removed from the Gulf and companies that buy very little oil themselves.
Why so? Because once energy pushes inflation higher, investors start demanding a higher return to lend governments money for 10 or 30 years through their bonds. That higher sovereign yield then becomes the base price on which much of the rest of the financial system operates.
This would be uncomfortable in any economic cycle, not just in the midst of a war. What makes it worse is that it comes on top of an 18-month period in which tariffs had already made the disinflation process more difficult and developed governments had entered the shock with large borrowing requirements.
The US Federal Reserve’s July Monetary Policy Report explains the sequence quite clearly. It notes that inflation began moving higher during 2025 itself, partly because increases in tariffs on US imports pushed up domestic prices of some consumer goods.
Inflation then rose again in March 2026 as energy prices surged after the US-Iran conflict began. Total personal consumption expenditures inflation reached 4.1% in May, compared with 2.5% a year earlier. Now we are in September and the situation has hardly changed.
Which is what makes this more than another oil problem. The world had not completely solved the previous inflation problem when the next one arrived.
From Oil to Bond
So, how does this shock travel from an oil surge to higher yields? The first part is straightforward. When crude prices rise, petrol and diesel become more expensive. But energy costs do not stop at the fuel pump. They impact freight, aviation, fertilisers, chemicals, plastics, and large parts of industrial production. Companies absorb some of the increase in their margins, but eventually a part of it finds its way into consumer prices.
The Bank of England gives a sense of how quickly all that can add up. According to its estimates, the direct impact of higher energy prices could add around 0.4 percentage points to UK inflation in the second half of 2026. Once the indirect effects are included, inflation in the fourth quarter could be over one percentage point higher than it would have been before the Gulf conflict began in February.
For central banks, this is where the problem becomes a headache. A temporary jump in oil prices can be handled. The bigger concern is what happens after that. For instance, workers asking for higher wages because living costs have gone up; businesses raising prices because their own costs have risen; and inflation expectations beginning to move higher.
A central bank cannot, of course, bring down the price of crude. What it can do is try to make sure that the oil shock does not become a broader inflation problem. That usually means keeping interest rates higher for longer than would otherwise have been necessary, even when expensive energy is already slowing economic growth.
Bond investors (largely institutional investors) then make their own calculation. Anyone lending money to a government for 10 years is not looking only at today’s policy rate. They are asking what inflation, interest rates and government borrowing could look like over the next decade. If those risks rise, they demand a higher return.
That is how an oil shock eventually reaches a government’s borrowing cost. And after resisting that transmission for several months, the bond market is now beginning to show it more clearly. Rising yields across developed economies suggest that investors are no longer treating expensive oil as just another commodity shock.
A Pre-existing Problem?
It would be wrong, however, to look at today’s bond yields and blame everything on the Gulf conflict. Much of the damage had already been done before oil became the latest problem.Look at what the chart above shows for 2020: Government money was extraordinarily cheap. The average 10-year bond yield was just 0.89% in the US and 0.37% in the UK. Germany’s was minus 0.51%, while Japan was effectively borrowing at zero. By 2025, those averages had climbed to 4.29% in the US, 4.58% in the UK, 2.61% in Germany, and 1.55% in Japan.
Oil did not cause that rise. The pandemic inflation shock, aggressive monetary tightening and the end of the zero-interest-rate era had already forced bond markets to reprice the cost of money. What the oil crisis has done is that it has arrived at a particularly bad time. Borrowing costs were already high and governments have much less room to absorb another inflation shock.
So, the key question is not whether oil created the borrowing problem. It did not. The question is whether the latest oil shock will make the situation worse – or prevent it from getting better. That is a far bigger possibility.
Governments would be able to cope with today’s high debt loads more easily if inflation continued falling. Central banks would cut rates and long-term borrowing costs would gradually follow. But if energy keeps inflation uncomfortably high for longer, some of that expected rate relief may be postponed. Every month that yields remain elevated creates another opportunity for maturing government debt to be refinanced at a higher cost.
A Problem Bigger Than Inflation
The US bond market offers another warning. If the rise in Treasury yields were mainly about inflation, some of the pressure should have eased as long-term inflation expectations came down. That has not happened.
The 10-year breakeven inflation rate averaged 2.25% in July, slightly below the 2.30% recorded in February. Yet the 10-year Treasury yield was substantially higher. The difference came from a rise in real yields; that is, the return investors demand after allowing for expected inflation.
There is another clue in the term premium, the extra return investors demand for locking their money into a long-term bond rather than repeatedly investing it in shorter-term securities. A Federal Reserve model estimates that this premium rose significantly between February (when the war started) and August. It is an estimate rather than an observable market price, so the precise number should be treated with caution. But the direction is important.
Bond investors are demanding more compensation for holding long-term US government debt. Inflation is part of that calculation, but it is not the only part. Investors also have to think about where interest rates go from here, how much debt the US Treasury will need to sell, and how uncertain all of those assumptions have become.
That makes the problem harder to dismiss as another temporary oil-driven inflation scare. Even if energy prices eventually settle and the immediate inflation pressure recedes, the forces keeping long-term borrowing costs high may not disappear with them.
What it Means for Markets
The market is now dealing with two problems at the same time. The first is the immediate one: Expensive oil keeps inflation higher, which, in turn, makes central banks more cautious about cutting rates, and pushes back the relief that borrowers and markets were expecting.
The second problem: Long-term borrowing costs have already moved far above the levels seen for much of the previous decade. Oil can add to that pressure, but it did not create it. Even if crude prices eventually settle, there is no guarantee that bond yields will simply return to where they were.
And that has consequences as government bond yields are the benchmark for a large part of the financial system. Companies borrow at rates linked, directly or indirectly, to sovereign and other benchmark yields. Higher risk-free rates also reduce the present value investors are willing to pay for future corporate earnings. And when government bonds themselves offer attractive returns, investors have less reason to take additional risk unless they are adequately compensated for it.
It is not, however, a direct or mechanical relationship. A rise of 20 basis points in the US Treasury yield does not mean every company suddenly pays 20 basis points more or that equity valuations fall by a predictable amount. But the starting point changes. The return investors demand before taking credit, equity, or currency risk moves higher.
That is also where India enters the story. Indian government bond yields have followed a different path from those in the US, UK, Germany or Japan. But Indian equities and bonds do not operate in isolation. They compete for the same global capital.
If an investor can earn substantially more from a US Treasury or another developed-market government bond than a few years ago, the return required to justify taking additional risk in India also rises. That does not automatically mean foreign money leaves India. But it does mean that Indian assets have a higher hurdle to clear.
And if developed-market bond yields remain elevated, that hurdle may remain high even after the immediate oil shock passes.
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