Oil is not just a cost at the pump. It is an input cost for airlines, haulage firms and factories, and it is one of the numbers bond investors and central banks watch most closely for early signs of inflation. That is how a barrel of crude can end up changing the share price of a company that has nothing to do with oil.

The Chain, Link by Link
How a rise in the oil price can end up changing what a share is worth.
  1. 1

    Oil price rises

    Crude oil trades on global markets and can reprice within minutes on news about supply or demand.

  2. 2

    Business costs rise

    Oil feeds into fuel, transport, plastics and chemicals. Airlines, haulage firms and manufacturers feel it first.

  3. 3

    Consumer prices follow

    Businesses pass some of the extra cost on to protect their margins. Spread across a whole economy, those price rises show up as inflation.

  4. 4

    Interest rates are expected to stay higher

    Central banks raise interest rates to bring inflation down. Investors start expecting rates to rise, or to stay high for longer.

  5. 5

    Bond yields rise

    Lenders to governments want a higher return to keep pace. Because the interest a bond pays is fixed, bond prices fall until a buyer at today's price earns that higher return.

  6. 6

    Future profits are worth less today

    Investors measure a company's future profits against what they could earn safely. A higher safe return raises that bar, so each pound of future profit is worth less today.

  7. 7

    Share prices adjust

    Investors pay less today for the same expected profits, and that shows up in the share price.

The links do not move at the same speed. The real economy (links 2 and 3) takes weeks to months. Markets often jump straight from link 1 to link 5 within hours, because traders act on what they expect inflation and interest rates to do. Each link can also break: a business may absorb a cost instead of passing it on, or a central bank may hold rates where they are.

Link 5 is where most explanations go wrong, so it is worth slowing down. A bond pays a fixed amount of interest, called the coupon, set on the day it is issued. The yield is different. It is the return a buyer earns if they buy the bond at today's market price and hold it to the end. The coupon never changes. The price does, and the yield moves with it.

What Happens to a Bond When Yields Rise
A simplified 10-year government bond, issued at £100.
Coupon (fixed)Market yieldPrice
The day it is issued£5 a year5%£100.00
New bonds now pay 6%£5 a year6%£92.64
Nobody will pay £100 for a bond paying £5 when new bonds pay £6. The old bond's price falls to about £92.64, the level at which a buyer collecting the remaining £5 payments plus £100 at the end earns 6% a year overall. Rising yields and falling bond prices are the same event described two ways. The figures are illustrative and assume all ten years remain.

That higher yield matters for shares because it changes a comparison every investor is making, whether they realise it or not: what can I earn safely, against what I might earn by taking risk.

Why a Higher Bond Yield Changes the Comparison
A simplified version of the comparison happening in investors' heads.
Government Bond
5%
A year, if held for all 10 years
Bought today and held to the end, the return is known in advance, provided the government pays its debts. Sold early, it is not: if yields rise in the meantime, the bond is worth less than was paid for it.
Stock Market, Long-Run Average
~8%
Historical average, not guaranteed
This average is not paid out evenly. It is made up of years of strong gains and years of sharp losses. The extra return over the bond is the reward for living with that uncertainty.
These figures are illustrative, not a forecast, and past performance is not a reliable guide to future returns. Here an investor is weighing a known 5% against a roughly 3-percentage-point extra return that is not certain and may not arrive in any single year. As the bond yield climbs, that gap narrows, and shares have to offer a more convincing case to be worth the risk.

Higher yields do not hit every company equally. What matters is when a company's profits arrive. The further away a pound of profit is, the more a higher interest rate shrinks what it is worth today.

Same Total Profit, Different Timing
Two hypothetical companies, each earning £100 over ten years.
Value today at 4%Value today at 6%Change
Company A: £10 every year£81.1£73.6−9%
Company B: nothing for 5 years, then £20 a year£73.2£63.0−14%
The same two-point rise in interest rates knocks about 9% off Company A's value but about 14% off Company B's, because more of B's profit sits far in the future. This is why fast-growing companies expected to earn most of their profit years from now tend to fall harder when yields rise. The figures are a simplified illustration, not a valuation of any real company.

The chain is not just theory. A version of it showed up in US markets in September 2026, with an important complication.

One Week in September 2026
Three readings from US markets around Wednesday 23 September 2026.
~$100
Brent crude oil had spent much of the month around or above $100 a barrel, near its highest level in months.
Above 5%
The yield on 10-year US government bonds rose to its highest level since 2007, a week after the US central bank raised interest rates.
Shares fell
US shares dropped on 23 September as the cost of safe borrowing jumped.
Oil was not the only force at work. The sharpest jump in yields that day came after a report showed US business activity growing faster than expected, which also pointed to higher inflation and higher interest rates. Two different causes travelled down the same chain at once. On other days, oil and yields have risen together without pulling shares down, when strong company earnings outweighed the higher rate applied to future profits.

That complication points to the last idea. Markets do not react to news on its own. They react to the gap between the news and what was already expected. If traders have spent weeks anticipating a rise in oil, much of its effect is already in bond and share prices before it happens, and the arrival barely moves anything. A smaller rise that nobody saw coming can move prices more. TEI calls this second-order thinking: asking not only what happened, but what the market had already priced in beforehand.

You can't predict. You can prepare.Howard Marks
01

Oil reaches share prices through interest rates, not directly.

A rising oil price feeds into inflation and interest rate expectations first. It is the resulting rise in bond yields that changes what investors will pay for future profits.

02

Rising yields and falling bond prices are the same event.

A bond's interest payment is fixed. When the return investors demand goes up, the only thing that can adjust is the price.

03

The further away the profits, the harder rising yields hit.

Companies expected to earn most of their profit years from now lose more value when interest rates rise than companies earning steadily today.

04

Markets react to surprises, not to raw numbers.

What moves prices is the gap between what happened and what was already expected. Expected news is often priced in before it arrives.

In short: oil moves share prices through the price of safe money.

When oil rises, business costs rise, then consumer prices, then the interest rates central banks set and lenders demand. Higher yields on government bonds raise the bar every other investment has to clear. Future profits become worth less today, and share prices adjust, most of all for companies whose profits are furthest away.

So next time a headline says oil is climbing, you can follow the chain yourself. Is this a surprise, or was it already expected? Are bond yields moving with it? How much of what you own depends on profits years from now? Those questions won't tell you what markets do next. They will tell you why your investments are moving, so you can decide calmly instead of reacting.