Our weekly SIC write-ups usually ask which sectors are most common or oldest. This week we ask a more practical question: how big is a typical company in each sector, and why does the answer change depending on whether you use an average or a median?
We took the first SIC code listed against each of the 650 companies Archive Partners tracks, grouped them into standard SIC sections, and compared turnover. Some 636 companies carry a usable code. Across all of them the median turnover is £14.6m, while the mean is £25.3m. That gap is the first clue: a small number of very large companies pull the average well above what a typical firm looks like.
The three biggest sectors look alike. Wholesale and retail trade (112 companies), manufacturing (111) and construction (95) dominate by headcount. Their medians sit between £15m and £20m: £20.0m for trade, £15.3m for manufacturing and £18.1m for construction. Their averages are higher, at £30.6m, £21.5m and £23.9m, but the gap is modest. These are broad sectors with plenty of mid-sized firms and no single dominant name, so the average is a reasonable guide.
Finance shows the distortion most clearly. The 43 finance and insurance companies have a mean turnover of £48.2m, almost twice the all-sector mean. The median is £24.6m, still the highest of any sector with a meaningful sample, but half the average. Anyone benchmarking a financial services supplier against the mean would overestimate what a typical counterparty looks like. The same effect appears among the 35 information and communications companies: a mean of £29.6m against a median of just £7.4m, with the largest single company at £276m.
Small samples need care. Energy has only four tracked companies, yet its mean turnover is £233m because one of them reports £926m. We would not read that as a sector story. Likewise education (eight companies, median £0.7m) and real estate (16 companies, median £1.9m) are thin, and a handful of entries can move the picture. As a rule of thumb, treat any section with fewer than 20 companies as an anecdote rather than a trend.
The small end of the table. Arts and recreation has a median of £2.6m across 16 companies, and hospitality, at 20 companies, has a median of £4.7m against a mean of £15.0m. In hospitality, a few large operators sit alongside many owner-run venues, so the headline average describes neither group well.
What this means for filings. Size shapes how a company files. Larger firms generally have more complex accounts, more officers and a stricter audit regime, while the smallest can use reduced disclosure. When you compare a company with its sector, comparing it with the sector median is almost always the fairer test, and checking how many companies sit behind the figure is the second.
A caution on the numbers. These figures cover a tracked group of 650 companies, not the whole UK register, and turnover is taken from the most recent accounts on file. The first SIC code listed is self-declared and not always the most representative. Treat the results as a snapshot of the companies we follow.
Each company profile on Archive Partners shows its turnover, SIC codes, county rank and accounts due date together, so you can run the same median comparison for any county or sector you care about. Start from a county page and work outwards.