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ANALYSIS
14 OCT 2026
Economy · Competition

Concentration has fallen in the UK's biggest industries, not the typical one

The Office for National Statistics says the top five firms' share of turnover fell from 45% to 38% between 2010 and 2025, weighted by industry turnover. Across industries counted equally, it is unchanged at 47%.

Noodle News data desk · reading time ~3 min
38%
Turnover share of the five largest firms in an average industry, 2025, weighted by turnover
47%
The same share with every industry counted equally, unchanged since 2010
700
Average Herfindahl-Hirschman index in 2025, down from 1,075 in 2010
What the data shows

Dominance by the largest firms has eased where the money is

New Office for National Statistics (ONS) figures, published on 13 October, show that large firms hold a smaller share of UK industry turnover than in 2010.1 Weighted by turnover, the five largest firms in an average industry took 38% of sales in 2025, down from 45%. The ten and twenty largest fell by similar amounts.

That fits the official picture from the Competition and Markets Authority (CMA), which found in 2024 that concentration had risen in the 2000s, then eased, and was no higher than in 1997.2 The ONS and CMA use different data and methods, so their levels should not be compared.

Exhibit 01
Share of turnover taken by the largest firms, 2010 and 2025
Source: ONS, Trends in UK industry concentration, 13 October 2026. Concentration ratios for four-digit industries, averaged using turnover weights, non-financial business economy. Rounded to whole percentages.1
The catch

The typical industry has not moved

The ONS also reports the spread across industries when each counts equally. On that basis the mean top-five share was 47% in both 2010 and 2025, and the median rose from 42% to 44%.1 A fall that shows only in the turnover-weighted figure must come from industries with large sales.

The ONS points to one: wholesale of fuels. In 2010, industries with a top-five share of 70% to 79% generated 19.2% of all turnover, mostly in this industry. By 2025 that industry's own top-five share had fallen to 57%.1 The ONS cautions that a few high-turnover industries can shift these figures.

Exhibit 02
Top-five share: weighted average against the typical industry
Source: ONS, as Exhibit 1. The ONS says the weighted and unweighted measures are not directly comparable in level, so read each pair for its change between years, not across groups.1
Key finding. The fall in concentration is real in the turnover-weighted data. It is not a general shift across industries.
Where it is highest

Utilities and manufacturing stay the most concentrated

Mining, energy and utilities has the highest top-five share, at 66% in 2025, down from 77% in 2010. Electricity and gas supply is the highest section at 74%. Construction is the lowest group at 14%, and real estate the lowest section at 10%.1

Exhibit 03
Top-five share by broad industry group, 2025
Source: ONS, as Exhibit 1. Turnover-weighted average top-five share, 2025, rounded.1
What we don't know

The ONS does not give a count of industries where concentration rose or fell, so the share of the economy that changed cannot be read off. It publishes most figures only for 2010, 2025 and selected years, and the full yearly series sits in an interactive chart and a dataset. Whether lower concentration means more competition is not answered here. The CMA's 2024 report also found that markups in Great Britain have risen by about 10% over 25 years and firm entry and exit have declined.2

Caveat
Caveat. The strongest objection is that these are not markets. An industry code can cover many separate products and places, so the ONS says the figures may understate concentration where firms actually compete, and that concentration does not by itself imply market power. The 2025 turnover values do not yet include the Annual Business Survey returns and may be revised, and the series is labelled official statistics in development. The weighted-versus-typical gap rests on the ONS's own figures, but they are not like-for-like, so the gap shows a difference in change, not a measured cause.
Method. Concentration ratios (CR5, CR10, CR20) are the share of an industry's turnover taken by its largest 5, 10 or 20 firms, calculated by the ONS for four-digit industries from the Inter-Departmental Business Register and averaged using turnover weights; the Herfindahl-Hirschman index (HHI) sums squared turnover shares across all firms. Figures are transcribed from the ONS bulletin, converted to whole percentages for display, and every printed value was checked against the published value. Unweighted means and medians are the ONS's distribution across industries, with values of 0.90 or more top-coded. The register excludes very small businesses and agriculture, finance, insurance and public administration. The CMA report is a separate, independent analysis using a different dataset and period; its levels are not compared with the ONS's here.
Sources.
  1. T1Office for National Statistics, Trends in UK industry concentration: 2007 to 2025, 13 October 2026. Retrieved 14 October 2026.
  2. T1Competition and Markets Authority, The State of UK Competition Report 2024, 24 October 2024. Retrieved 14 October 2026.
Production. Researched, written and checked by an AI system working to the Noodle News standards; edited and published by the Noodle News editor.
Corrections. None. Material corrections will be logged here with date.
Figures to 14 Oct 2026. Noodle News · v1.0 · uk-industry-concentration-weighted-gap.