Writing an organic revenue growth definition that holds up across a whole portfolio

Two show directors are looking at the same portfolio review. One of them says the business grew 12.6 per cent. The other says it grew about one per cent. Both are reading from the pack, and both are right, because nobody has written down an organic revenue growth definition that says which exclusions apply before a growth rate goes on a slide.

This is the least glamorous document in an event finance function and the one that settles the most arguments. It takes an afternoon to write and it needs to survive being read by somebody in the commercial team who was not in the room.

What does organic actually have to exclude?

Four things, for a portfolio of shows, and the fourth is the one general finance templates leave out.

Acquisitions, until the acquired business has been owned long enough to appear in both periods. Disposals, removed from the comparative so the prior year does not carry revenue the current year cannot. Currency translation, so a portfolio selling in euros, dirhams and Singapore dollars is measured on trading rather than on the exchange rate. And event cycling, because a portfolio containing biennials and triennials reports growth in some years that is purely the calendar.

RELX PLC's 2025 annual report on Form 20-F sets out its version in one sentence: "Underlying revenue growth rates are calculated at constant currency and exclude revenue from acquisitions until twelve months after purchase, revenue from disposals and assets held for sale, print and print-related revenue and exhibition cycling."

Read that as a checklist rather than as prose. Every clause is a decision somebody made and can defend, and the phrase "until twelve months after purchase" is doing more work than its length suggests.

The list of what stays inside matters as much. A show the group launched itself belongs in organic growth from its first edition, because building it was the organic activity, and excluding launches would let a business that grows by launching report zero growth forever. I would hold that line even when the launch year is ugly, which it usually is. A show that grew because the team raised the rate card by 8 per cent belongs in organic growth too. So does one that shrank because a competitor took two halls of exhibitors. Organic growth is meant to be the number that gets somebody promoted or fired, and every exclusion added to it moves a piece of the business outside that judgment.

Working the bridge on a portfolio of eleven shows

Take a portfolio reporting 39.2 million this year against 34.8 million last year. Reported growth is 4.4 million divided by 34.8 million, which is 12.6 per cent, and that is the number that reaches the board unless somebody stops it.

Two things sit inside that 4.4 million. One show was acquired in March this year and contributed 2.9 million of revenue between then and the year end, against nothing in the comparative because the group did not own it. Currency movements added 1.1 million to the translated value of the overseas editions.

Strip both out. Organic revenue this year is 39.2 million less 2.9 million less 1.1 million, which is 35.2 million. Against the 34.8 million comparative, that is 0.4 million of growth, or 1.1 per cent.

The gap between 12.6 per cent and 1.1 per cent is 11.5 percentage points, and every point of it is real. The group did buy a show, and the euro did move. What the two figures answer are different questions, and the failure mode is publishing one of them without saying which question it answers.

What a published bridge looks like when the arrows point the other way

The gap runs in both directions, which is easier to believe with a real example than with an invented one.

RELX reported group revenue of 9,590 million pounds for 2025 against 9,434 million for 2024, up 2 per cent. Its underlying revenue growth for the same period was 7 per cent, worth 586 million pounds. The distance between them is set out line by line in the same filing: exhibition cycling of negative 48 million, acquisitions of 14 million, disposals of negative 91 million, print and print-related activities of negative 109 million, and currency effects of negative 196 million.

Add those to the 2024 base and the arithmetic closes on 9,590 million exactly. That is what a defensible bridge looks like. Five named lines, each one traceable, and a reader who disagrees with a line can say which line and by how much.

The organiser scale version of the same discipline is a five row table in the board pack rather than a paragraph of explanation, and it costs about twenty minutes a month once the underlying data has the fields for it.

Why is the twelve month boundary the hard part?

Because an acquisition made in March does not politely wait for a year end, and a portfolio of annual shows has a further complication that a subscription business does not.

Suppose the show acquired in March runs in October. In the first year of ownership the group gets one edition of it. In the second year the group gets one edition again, and the acquisition has now been owned for more than twelve months, so it enters organic growth. That works cleanly.

Now suppose the show runs in February. Buy it in March and the first edition the group owns runs eleven months later, in the following February, which falls in the second year of ownership. The first year of ownership contains no edition at all. Applying a flat twelve month rule puts the show into organic growth in a year where the comparative contains zero revenue for it, producing an organic growth rate that includes a show appearing from nothing.

The fix is to state the boundary in editions rather than in months for the event lines: an acquired show enters organic growth once both periods contain one edition of it. Say so in the definition. A group that does not say so will find the rule being interpreted differently by whoever runs the numbers that quarter, and the difference will not be visible in the output.

Disposals have the mirror problem and a simpler answer, because the disposal date is known and the comparative can be trimmed to it. Where the sale happens mid year, the honest treatment removes the disposed revenue from both periods rather than only from the current one. A group that trims only the current year gets a comparative carrying nine months of a business it no longer owns, which understates organic growth by the whole of that nine months and does it silently.

Changing the definition without breaking the series

Definitions do change, and hiding the change is worse than making it.

RELX refined its own definition for 2025 to exclude print and print-related results following a change in segmental reporting, and said so in a footnote to the revenue bridge, with prior period figures restated to reflect the change. That is the full treatment: name the change, restate the comparative, and let a reader see both.

Informa PLC puts the underlying warning plainly in the glossary of its 2026 half year results, noting that the terms "adjusted" and "underlying" are "not defined terms under IFRS and may not therefore be comparable with similarly titled measurements reported by other companies". Two event groups can both report organic growth, both be correct, and be measuring different things.

Inside one business the equivalent risk is smaller and more annoying. A definition that drifts means this year's 1.1 per cent cannot be compared with the 4.3 per cent from three years ago, and nobody notices until somebody plots the series. Keeping the definition still is worth more than getting it perfect.

Where this stops

Organic growth is a comparability device with a real cost, and the cost is that it hides things the business needs to know.

A group whose reported growth is 12.6 per cent and whose organic growth is 1.1 per cent has genuinely grown 12.6 per cent in cash terms. The bills get paid out of reported revenue. Presenting organic as the true number, and reported as noise, is the mistake that runs in the opposite direction from the one this post opened with, and a management team that acquires every year can hide behind an organic figure indefinitely.

The other limit is that organic growth says nothing about which shows grew. A portfolio at 1.1 per cent organic could be eleven shows all growing slightly, or four shows growing strongly and seven declining. Answering that needs a fixed set of editions held constant across both periods, which is a related calculation with its own construction rules. The cycling exclusion also deserves its own treatment, because the biennial adjustment is the piece most organisers get wrong first, and the currency step depends on which exchange rates you restate at.

The first step this week

Write the definition as five numbered exclusions on one page, then hand it to the person who builds the board pack and ask them to reproduce last year's headline growth rate from it without asking you a question. Whatever they have to ask about is the ambiguity you are going to argue about in six months. The page belongs in the same folder as the rest of the finance reporting definitions, where the next person can find it.