Best of both is the most expensive way to integrate two companies

A synergy case assumes the combined organisation is the better half of each. In practice it is a third operating model that neither company has run before, and learning to run it can cost about as much as the synergy was supposed to save.

The synergy number is set before anyone knows how the companies work

The synergy figure is set in the deal model, months before anyone has seen how either company actually decides anything. It is a percentage of a combined cost base, not a design. By the time somebody has to make it real, the number has been repeated in enough rooms to have become a commitment.

Best of both is a third company

Faced with two ways of working, an integration team does the reasonable thing and takes the better half of each. The pricing model from one, the account structure from the other, the planning cycle from the first, the escalation path from the second. Every one of those choices is defensible on its own.

The combined company ends up running an operating model that neither of them has run before.

The cost shows up as coordination. More meetings to align, more exceptions to arbitrate, more decisions escalated because the rule is new and nobody trusts it yet. That coordination is paid for in exactly the months the synergy was supposed to land, which is why the case slips a year and then gets quietly rebased.

Pick a base, port the exceptions

The alternative is less elegant and much faster. Choose one company’s operating model as the base, in full. Then port only the exceptions from the other that you can name, justify and give an owner. You will keep some things that are worse on paper, because people already know how to run them.

Choosing the base means one side loses, which is why it is often avoided and handed to a workstream instead.

What a sponsor should ask for

Ask for a short answer to three questions rather than a full integration plan: which operating model is the base, which exceptions survive and who owns each, and which decisions move on day one. If those cannot be answered inside a month, the synergy number is a forecast and not yet a plan.

This is the kind of question an OD Blueprint answers, and the kind an OD Verdict tests when the integration design already exists.