Common Questions

Why did US inflation jump so sharply in March 2026?: March 2026 US CPI rose 0.9% month-on-month, the largest increase since 1967. Gasoline prices surged 21.2% following the blockade of the Strait of Hormuz, which cut off roughly 20% of global oil supply.Source: Bureau of Labor Statistics March 2026 CPI release
What is the difference between core CPI and headline CPI?: Headline CPI includes all goods including food and energy. Core CPI strips those out to show underlying inflation trends. The Federal Reserve focuses on core CPI because energy and food prices are volatile and often driven by supply shocks outside its control.Source: Bureau of Labor Statistics methodology
How does inflation affect the 2026 US midterm elections?: CPI is the primary economic indicator cited in midterm campaign messaging. High energy prices driven by the Iran war are a liability for incumbents. Voters consistently rate cost-of-living as a top voting issue, and elevated CPI feeds directly into consumer sentiment surveys.Source: University of Michigan Consumer Sentiment Index; midterms coverage
Does AI investment make inflation worse?: Goldman Sachs calculates that data-centre electricity demand will ADD approximately 0.1 percentage points to core US CPI annually through 2026-27, a modest but measurable effect as AI infrastructure buildout drives power-grid investment.Source: Goldman Sachs AI capex research 2026
How does the Hormuz blockade push up prices in the shops?: Blocked Hormuz oil supply raises crude prices, which feed into petrol and diesel costs within weeks. Diesel is used to transport most goods, so higher diesel prices raise the cost of food, manufacturing, and distribution across the economy, lifting CPI broadly.Source: Iran conflict coverage; BLS gasoline CPI component data

Background

The Consumer Price Index (CPI) has moved to the centre of political argument across all three active Lowdown topics. US CPI, published monthly by the Bureau of Labor Statistics, rose 0.9% month-on-month in March 2026 — the largest single-month increase since 1967 — driven by a 21.2% surge in gasoline prices following the blockade of the Strait of Hormuz. Before that blockade, fuel had already risen 36% from pre-war levels: the largest single-month fuel rise since 1991. Goldman Sachs calculates that data-centre electricity demand alone adds approximately 0.1 percentage points to core US inflation annually through 2026-27 — tying AI capital expenditure directly to CPI.

CPI measures the price change of a weighted basket of goods and services bought by a typical urban household. The basket and its weightings are reviewed periodically: housing (shelter) carries the largest weight in US CPI at roughly 36%, followed by food and transport. Headline CPI includes energy and food; core CPI strips them out and is what the Federal Reserve watches most closely when setting interest rates. The UK equivalent is published by the Office for National Statistics, while the Eurozone uses the HICP (Harmonised Index of Consumer Prices). All three are calculated monthly. The University of Michigan Consumer Sentiment Index tracks consumer expectations of future inflation, which feeds into actual price behaviour through wage-setting negotiations.

Cost-of-living is the issue that decides elections. For the US 2026 midterms, CPI is the single most-cited economic indicator in campaign messaging: Republican incumbents face pressure on energy prices inflated by the Iran war, while Democrats frame the same numbers as a national-security consequence of Middle East instability. On the AI and jobs beat, elevated CPI constrains the Fed's room to cut rates — meaning the cost of capital for AI infrastructure stays higher for longer, slowing the very deployment that is reshaping labour markets. UK vacancies frozen at 721,000 for six consecutive months alongside persistent services inflation show the same wage-price tension in a different labour market.

How the World Sees Them

Eurozone

The ECB targets HICP below 2%. Energy pass-through from Hormuz disruption varies across member states depending on import mix, making a uniform rate response politically contested.

United States

The Fed uses core CPI to calibrate interest-rate decisions. War-driven energy inflation complicates policy: headline CPI is surging but the Fed risks overtightening if it ignores the supply-shock component.

United Kingdom

ONS CPI feeds directly into public-sector pay review bodies. Persistent services inflation above 5% limits Chancellor flexibility and prolongs the cost-of-living squeeze on households.

Emerging markets

Dollar-denominated oil import costs amplify domestic CPI in countries with weaker currencies, tightening fiscal space and risking social unrest in the most fuel-dependent economies.