The number is the easy part. The eighteen months after are the deal.

By Tim Sutton, senior reputational adviser and PR-agency M&A counsel · July 2026

When my partners and I sold our agency, I spent the final week before completion worrying about the wrong things. The warranties. The disclosure letter. The exact wording of the earn-out schedule.

All of it mattered, and none of it was the thing that would decide whether the sale had been worth doing. I did not understand that until later, by which point a good many of the people who had built the firm with us were gone, I was in a larger job somewhere else, and I was telling myself the deal had been good for everyone.

I have been on both sides of that table. With my partners, I once sold a company and have bought others since, both for my previous employers and as an independent consultant, so I have learned to read a deal from the buyer's chair too, not only the seller's. And I have watched a fair number of founders make the mistake I made. They treat the sale as an event that ends at signing. It does not. The sale is the eighteen months that follow it, and the value is quietly won or lost in a set of things the deal process barely mentions.

This is not a new mistake, but it is about to be made at scale again. Omnicom completed its takeover of Interpublic in late 2025. As I write, in July 2026, Sky, owned by Comcast, has agreed to buy ITV's broadcasting and streaming arm for up to £1.6bn. Every such deal is written up as a triumph on the day it is announced. The real work, the part nobody photographs, starts the following Monday.

What you pay for is rarely what survives the integration

Here is the uncomfortable thing a buyer rarely says out loud and a seller rarely asks. What you are paying for is almost never the thing that survives the integration.

You buy an agency because a particular client trusts a particular person in a particular room. That trust is the asset. It does not appear on the balance sheet, it cannot be warranted, and it is the first thing an integration puts at risk. You merge the P&L, you rename the brand, you move the reporting line, and eighteen months later the person who held the relationship is managing a matrix instead of managing a client. The trust was in the room. The room is gone.

Every acquirer says people matter. But saying it and resourcing it are different things, and the gap between the two is where most of the value leaks out. The financial model in an agency deal gets a hundred hours of attention. The human model gets a meeting. Then the human model turns out to be the one that decides whether the deal is remembered as a success.

So where does the value actually go?

"Culture" on its own is a word that lets everyone off the hook, so let me be specific. There are three places.

The first is the second tier. Not the founders, who are locked in by the earn-out and closely watched, but the layer just beneath them. The senior people who never held equity, who built and hold the client relationships day to day, who get no cheque at completion and a new organisation chart in the new year. In my experience they are the most likely to leave in year two, and when they go the clients tend to follow them out of the door. A buyer who spends a hundred hours modelling the founders' lock-in and none on the second tier has done the wrong diligence. I have sat in integrations where the founder was retained, celebrated, and quietly irrelevant, while the three people who actually held the accounts had already taken calls they would not have taken a year earlier.

And if you are the seller, there is a sharper reason to watch that layer than sentiment. In most deals the earn-out that decides what a founder actually takes home is measured over precisely these first eighteen months. The value walking quietly out of the door is the value your own consideration is priced on. You are not only losing colleagues. You are lowering your own number.

The second place is speed. An acquirer buys a business precisely because it does something the acquirer cannot, and then sets about making it behave like everything else it owns. Rebrand it, restructure it, then move it onto the group's systems. Each step is defensible. Together, done too fast, they strip out the very things that made the firm worth buying. I once watched a buyer move a boutique onto the parent's timesheet and sign-off systems inside a quarter, and half the reason clients had paid a premium, the speed of it and the informality, was gone by the summer. The model is not the firm, and the buyers who forget it pay twice, once at completion and again when the thing they modelled walks out.

The third place is the founder's own head. You expect to sell on the Friday and stop being the owner on the Monday. You do not. The title changes overnight. The identity takes years, if it ever fully goes. I have sat with founders three months after completion who could not understand why a decision had gone against them, and the answer is always the same and never welcome. You sold control along with the equity, and you did not feel the weight of that sentence until the first decision you disagreed with was taken without you.

The exits that work look boring from the outside

None of this is an argument against selling. Consolidation is, to my mind, a rational answer to a market where scale increasingly wins, and for a founder at the right stage a good sale is the right answer to the right question. The best exits, in my experience, are the ones that look boring from the outside. A sale that works has no drama in it. The founders get the value they were promised and are treated with respect throughout. The buyer ends up with an intact business. Nobody important leaves. The returns arrive roughly on schedule. That is the whole point, and it is precisely why the deals that work make for such poor reading.

What a founder should actually do

So what does a founder actually do with this, a year or two out from a conversation they have not yet had?

Mostly, they widen the diligence. The buyer will run something forensic on them. Almost nobody runs the same exercise back on the buyer. What happened to the last three firms this acquirer bought? Where are the senior people from those firms now, and I mean the second tier, not the founders? If the honest answer is that they left inside two years, then the price on offer is a gross number, and the net number, the one that accounts for what walks out of the door, is considerably lower. Far fewer sellers run that check than you would expect. It is the single most useful afternoon's work available to them, and it costs nothing but the discomfort of the answer.

They also get honest about their own dependence. The very quality a buyer discounts them for, that the firm leans too heavily on the founder, is the same quality a client pays a premium for while the firm is still independent. Before a process, that dependence is an advantage to be pressed. After a sale, it becomes a risk to manage. Getting those two the wrong way round is most of the regret I see.

And they count what leaves before the leavers do the counting for them. The number a buyer pays is for the relationships. The relationships are the one asset in the building that can resign.

I said at the start that I got this wrong on my own sale, and I did. If I have any standing to write about it, it is not because I once ran a clever process. It comes from having since sat on the other side of the table, watched the value I have described leak out of deals that looked immaculate on the day, and had the humbling experience of recognising my own younger mistakes in founders considerably more sophisticated than I was. Helping founders run this check on a buyer, and helping buyers run it on themselves, is much of what I now do.

The question that is never answered at signing

The consolidation moving through this industry will produce a long run of announcements over the next few years, and most of them will be a genuine success for somebody. The question worth holding on to, whichever side of the table you are on, is not what the firm is worth. It is whether the version of it the buyer wants will survive contact with the version the clients actually pay for.

That question is never answered at signing. It gets answered eighteen months later, by the people the model never named, in conversations the deal team was never in.

This piece sits alongside the soft issues that decide whether an agency deal works, and the earn-out that quietly prices these eighteen months is the subject of where a PR agency deal is won or lost.

See the sell-side readiness scorecard Speak with Tim in confidence

Tim Sutton is a senior reputational adviser to boards in their hardest moments and counsel to PR-agency principals on both sides of a transaction. timsuttonpr.com · LinkedIn · Privacy · Legal