The FTSE 100 and FTSE 250 measure different parts of the UK equity market. Neither is a direct reading of household finances or UK economic growth. To interpret a move, identify the index, its largest exposures, the return measure and the observation time.
FTSE 100 vs FTSE 250 at a glance
| Question | FTSE 100 | FTSE 250 |
|---|---|---|
| Market segment | 100 large UK companies meeting the series rules | 250 mid-cap companies outside the FTSE 100 |
| Weighting | Investability-adjusted market capitalisation | Investability-adjusted market capitalisation |
| What it is not | An equal-weighted survey of UK businesses | A purely domestic UK portfolio |
FTSE Russell ranks companies by full market capitalisation for selection, then applies investability adjustments to index weights. Eligibility, liquidity screens and review buffers also matter: the indexes are not simply an unrestricted ranking of every London-listed security. See the FTSE 100 overview and the FTSE UK Index Series ground rules.
Why the indexes can move in opposite directions
A UK listing does not mean that all a company’s sales are earned in Britain. FTSE Russell’s research on geographic revenues shows substantial international exposure in the FTSE 100 and overseas exposure in the FTSE 250 too. The mix differs, so the same domestic news need not affect both baskets equally. Source: LSEG research on UK index revenue exposure. That research is historical context, not a current constituent-weight snapshot.
Our interpretation checklist is to ask three separate questions: which companies contributed most to the move, what businesses they operate, and where their cash flows originate. A rise led by internationally exposed firms does not, by itself, establish that domestic consumer demand improved.
Currency has two different roles
First, a company’s operating results can be exposed to exchange rates through sales, costs, debt and hedging. A weaker pound is not automatically good for every exporter: imported inputs or foreign-currency liabilities may offset some benefit. Check the company’s own currency disclosures rather than applying one rule to an entire index.
Second, an overseas investor may translate a sterling-denominated holding into a different home currency. These are distinct questions; a company’s business exposure is not the same as the investor’s conversion return.
Hypothetical calculation: if an investment rises 5% in pounds while the pound falls 4% against the investor’s home currency, its translated return is (1.05 × 0.96) − 1 = 0.8%, before costs and taxes. This example assumes no currency hedge and is not a reported FTSE return.
A five-minute UK market reading checklist
- Identify the series: FTSE 100, FTSE 250 or a fund with a similar name. Read the fund’s benchmark and current holdings.
- Match the measurement: compare percentage changes over the same interval. Do not compare one index’s point gain with another’s.
- Check dividends: a price index and a total-return index measure different things. Use matching return variants and currencies.
- Inspect the drivers: distinguish a few large constituents moving from broad participation across the basket.
- Record timing: include date, time zone and whether the source is delayed, intraday or an official close.
Use the economic calendar to identify scheduled releases and the stock heatmap to explore available market views. Check each tool’s market selection and data timing; a widget is not the official index methodology.
Common questions
Does a higher FTSE index level mean better value?
No. Index points are a measurement scale, not a valuation ratio. Assessing value requires earnings, cash flows, risks and the price paid for them.
Is the FTSE 250 automatically the better growth investment?
No. A market segment is not a return promise. Suitability depends on the actual exposure, costs, time horizon and ability to tolerate losses.
Where should I check the latest constituents?
Use the index provider’s current materials and the relevant fund’s dated holdings. Old company lists can become inaccurate after reviews and corporate actions.
Correction note: this replaces unsupported 2026 sector forecasts and the earlier live-update claim. It does not recommend individual shares. Cover: AI-generated conceptual illustration, not market data. Corrections policy.