Guides / What is the FTSE 250? The index of mid-sized UK companies explained
What is the FTSE 250? The index of mid-sized UK companies explained
The FTSE 250 is a FTSE Russell index of mid-sized UK companies listed on the London Stock Exchange's Main Market. It holds the next 250 UK companies by market capitalisation after the FTSE 100, and its membership is reviewed every quarter.
Short answer: a "FTSE 250 business" is a company that sits in the FTSE 250 right now. The label describes where the company ranks by size at the last review. It says nothing about quality, safety or future returns.
What the FTSE 250 is
The FTSE 250 is one of the headline indices in the FTSE UK Index Series, which FTSE Russell (part of LSEG) runs. LSEG describes it as the mid-sized companies not covered by the FTSE 100, making up roughly 15% of UK market capitalisation.
An index is a rule-based basket of companies. Constituents are weighted by their market value, adjusted for free float (the shares that are actually available to trade), so larger members count for more. If you are new to the basic idea, the FTSE 100 guide covers it, and this page does not repeat it.
How a company qualifies
Under the ground rules, a company has to clear several hurdles before its rank matters:
- Listing. Only equity shares in the FCA's commercial companies or closed-ended investment fund categories, admitted to the Main Market of the London Stock Exchange, are eligible.
- Nationality. FTSE Russell assigns each company a nationality, and these indices only include UK companies.
- Free float. At least 10% of the shares must be freely available to trade.
- Liquidity. The shares must pass a liquidity test, which means they trade often enough to count.
Eligible companies are then ranked by full market capitalisation, the total value of their shares. The FTSE 100 is the largest 100 that qualify. The FTSE 250 is the next 250 outside the FTSE 100. Together they make up the FTSE 350.
Ranked 101st to 350th is a good rough guide, but it is not exact on any given day, because of the buffers explained below.
FTSE 250 versus FTSE 100
The main difference is size. Most of the rules are shared:
- Both use the same ground rules, the same eligibility screens and the same quarterly review.
- Both are weighted by free-float-adjusted market value.
- Both include only UK companies listed on the Main Market.
A company moving between the two has not become better or worse. Its market value has moved relative to its neighbours.
How companies move at the quarterly review
FTSE Russell reviews the FTSE UK Index Series every quarter, in March, June, September and December. The review uses data from the end of the Tuesday before the first Friday of the review month. Changes take effect after the close of business on the third Friday of that month, so they apply from the following Monday.
The ground rules use buffers so that companies do not bounce between indices over small moves in rank:
- A company joins the FTSE 100 if it has risen to 90th or above. A FTSE 100 member leaves only if it has fallen to 111th or below.
- A company joins the FTSE 250 if it has risen to 325th or above. A FTSE 250 member leaves only if it has fallen to 376th or below.
- A company removed from the FTSE 100 normally goes into the FTSE 250, and a company promoted to the FTSE 100 leaves the FTSE 250.
- A company removed from the FTSE 250 normally goes into the FTSE SmallCap.
So a company ranked 95th can still be in the FTSE 250, and one ranked 105th can still be in the FTSE 100. FTSE Russell publishes the outcome of each review.
Why every FTSE 250 list goes out of date
A list copied into an article, a spreadsheet or a forum post is fixed on the day it was made. The index is not. Each quarter companies are promoted, relegated or replaced, and takeovers and delistings can remove members between reviews.
That is why this page does not list members. For the current constituents, use the official sources:
- the London Stock Exchange's FTSE 250 page, which has a constituents tab
- FTSE Russell's UK index pages on LSEG's website, which link to factsheets and the ground rules
If a third-party list gives a count very different from 250, check its date and whether it counts share lines or companies. A company with more than one listed share class can have more than one line in the index.
What the FTSE 250 contains, in general terms
The index mixes businesses from across the economy, because mid-sized companies are not tied to one industry. Two points are useful to know:
- Investment trusts can be members. The ground rules allow closed-ended investment funds, and FTSE Russell publishes a separate "FTSE 250 ex Investment Companies" index that leaves them out. Some members hold portfolios of other investments instead of running an operating business.
- Some investment vehicles are excluded. Venture capital trusts and split capital trusts with separate income and capital share classes are not eligible.
MarketFrame's investment trusts sector page shows how news about trusts in the FTSE 100 reads day to day.
How to read news about a mid-cap company
The same habits work at any size of company, but some matter more for mid-caps:
- Start with the company's own announcement. Results, trading updates and deals are published through regulatory announcements and on the company's investor relations pages. Coverage of them comes second.
- Separate facts from opinion. What was announced, by whom and when? Then ask what the writer thinks it means.
- Watch the volume. Mid-caps usually get far less coverage than FTSE 100 companies, so one or two stories can look louder than they are.
- Check index news against the official review. Headlines such as "tipped for promotion" are guesses until FTSE Russell publishes the result.
News tone tells you how coverage reads. It is not a share-price forecast. A cheerful headline does not mean a price will rise, and a gloomy one does not mean it will fall.
Where MarketFrame fits
MarketFrame covers FTSE 100 companies only. It reads UK business news each morning and gives each company a tone score from -10 (clearly bad news for the company) to +10 (clearly good). The score describes news coverage. It is not share-price data, a forecast or investment advice. It is free to read, with an archive from 30 September 2026.
If you are reading about a FTSE 250 company, MarketFrame will not have a score for it. A company promoted into the FTSE 100 becomes part of the coverage universe. To see how this works for the larger companies, start at the daily FTSE 100 news hub, browse past daily overviews, or open any company or sector in the news analysis index.
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Questions people ask
What is the FTSE 250?
It is a FTSE Russell index of mid-sized UK companies on the London Stock Exchange's Main Market. Its ground rules define it as the next 250 UK companies by full market capitalisation outside the FTSE 100, after liquidity and free float screens.
How many companies are in the FTSE 250?
The ground rules set it at 250 companies. A company with more than one listed share class can have more than one line in the index, so a count of lines can come out a little higher. For the current figure, use the official FTSE Russell or London Stock Exchange pages, not a copied list.
What is the difference between the FTSE 100 and the FTSE 250?
Size. The FTSE 100 holds the largest 100 qualifying UK companies by full market capitalisation, and the FTSE 250 holds the next 250. Both follow the same FTSE UK Index Series ground rules and the same quarterly review.
How does a company get promoted from the FTSE 250 to the FTSE 100?
At a quarterly review, a company is added to the FTSE 100 if it has risen to 90th or above by full market capitalisation. A FTSE 100 company is removed if it has fallen to 111th or below. Companies that leave the FTSE 100 normally join the FTSE 250.
Where can I find the official list of FTSE 250 companies?
FTSE Russell publishes index information on LSEG's website, and the London Stock Exchange's FTSE 250 page has a constituents tab. Both update after each review, and copied lists do not.