Foundations
Part of What England buyers should check before choosing a paid search agency
How to read PPC agencies market size estimates for the UK
No official series reports the PPC agencies market size in England. Here is how the estimates are built, which sources count, and how to label a UK-wide total.
What to take away
- The ASA's online remit now takes in paid ads on social platforms as well as search, so one code covers both buying teams.
- There is no official series for the PPC agencies market size in England, so every published total is an estimate with named inputs.
- Spend keeps shifting into formats that sit beside search, so a search-only count understates the sector.
- Agree the definition before the number, and decide whether you are counting fees, billings or both.
- The England market guide for PPC agencies sets out the definitions used throughout this section.
Why no official figure exists
Registers and surveys answer different questions. Companies House filings, submitted for each financial year, count registered companies rather than agency revenue. Trade bodies count members rather than the whole market. Neither is a market measure on its own. Official business registers exist to support sampling, not to size one service line.
An England figure has to combine a company count, a spend estimate and an assumption about typical fees. Every step adds error.
A bottom-up estimate starts with client demand. A top-down estimate starts with total advertising spend. Both are defensible when the inputs are visible.
A quick worked example puts numbers on those inputs. Take 1,500 search agencies in England with average fee revenue of £120,000 each, which gives £180m a year. Take UK search adspend of £10bn with agencies keeping 10% in fees, which gives £1bn.
The two routes leave a range of roughly £180m to £1bn a year. The inputs are illustrative examples rather than measured totals.
Most published data covers the UK, not England alone. Scotland, Wales and Northern Ireland sit inside the same totals. An England-only number needs a stated apportionment.
Take the same £10bn UK total. Splitting it 84% to England by population gives £8.4bn of England media billings. At a 10% fee rate that is £840m (illustrative example). A share weighted by regional adspend would come out higher, because London and the South East carry more spend per head (illustrative example).
Written assumptions travel well. A footnote naming the source, its period and its geography lets a colleague rebuild a total without asking you.
Definitions that move the number
Two agencies with the same clients can publish very different totals. The gap is usually definitional rather than arithmetic.
Billings vs revenue conventions
Billings basis
- Reported total
- £1m billings
- Fee assumption
- 10% management fee
- Same client media
- £1m booked
- Rule to apply
- Pick one convention
Revenue basis
- Reported total
- £100,000 revenue
- Fee assumption
- 10% management fee
- Same client media
- £1m booked
- Rule to apply
- Apply every time
Media billings are the biggest swing factor. An agency booking £1m of client media for a 10% management fee can report £1m in billings or £100,000 in revenue (illustrative example). Pick one convention and apply it every time.
Agencies price in different ways, from a percentage of media spend to a fixed retainer. A retainer of £2,500 a month and a percentage fee on the same account can produce similar annual totals (illustrative example).
Format scope is the second swing. Sponsored content on LinkedIn is a paid format, and the platform's sponsored content documentation describes how it is bought. Whether it belongs in a PPC market figure depends on the question you are answering.
Sources worth trusting
Start with primary documentation, not commentary that recycles another estimate.
The IAB UK's account of its own history explains how the digital advertising trade body formed in 1997, which helps when you weigh its market material. The IAB UK also compiles the UK digital adspend figures with PwC, which cover the previous calendar year.
Trade body material is useful for direction and format splits, but it is not audited revenue data.
A source you can name and date is worth more than a chart with no attribution.
The UK advertising codes cover non-broadcast ads, and paid search falls inside that scope. The ASA has enforced them since 1962, and the codes say nothing about market value.
If you are sizing a new service line rather than a market, see commercial opportunities for PPC agencies in England.
Choosing an estimate method
Match the method to the decision. The table below shows which input suits which job.
Choosing an estimate method
Quoting a market size to a client?
Use a range, name each source
Comparing paid search with paid social?
Choose
- Quoting a market size to a client
- A range, with each source named
- Comparing paid search with paid social
- Billing data from the same period
- Sizing a new service line
- Company counts plus trade body data
- Weighting England against the UK
- A stated apportionment method
Avoid
- Quoting a market size to a client
- A single round number
- Comparing paid search with paid social
- Mixing periods or definitions
- Sizing a new service line
- One competitor's published revenue
- Weighting England against the UK
- Silent UK-wide numbers
Ranges beat point estimates when the inputs are surveys rather than audited accounts.
State the period as well. A total from one year and a total from the next are not comparable if the definitions moved in between.
For example, a team paying £400 a month for search management belongs in a fee-based count, not a billings count.
Common questions
Is there an official PPC agency market size for England?
No. Official output statistics group advertising with other business services, so they rarely isolate agency revenue. Treat any agency-specific total as an estimate.
Why do two estimates differ by so much?
Usually because one counts media billings and the other counts agency fees. Scope differences, such as whether paid social is included, add a second gap.
Does the CAP Code apply to paid search ads?
Yes. The codes cover non-broadcast advertising, and the ASA enforces them across paid search. Budget time for checking ad copy and claims.
Should I quote a UK or an England figure?
Quote the geography your sources cover. If the inputs are UK-wide, label the answer UK-wide. An England-only claim needs its own apportionment note.
