The brand question in a merger is almost always answered late, badly, and by exhaustion.
There is a reason for that. In the months around a deal, brand sits below legal, financial, systems and people on every list, and it sits there for defensible reasons. Nobody ever lost a deal over a positioning statement. So the decision gets deferred, and deferral has a default outcome: both brands continue, both stories continue, and the merged business spends its first two years in market describing itself as the combination of two things customers used to choose between.
That is not a position. It is an announcement.
The specific failure mode is additive language. We bring together the X of A and the Y of B. It is the most common post-merger message in existence and it fails for a simple reason: customers did not want a combination. They chose one of you, for a reason, and the merger has just told them the reason may no longer apply.
The second failure mode is the treaty. This is where the position is negotiated between two leadership groups who each need to protect their people, their clients and their sense of what the business is for. What emerges is technically agreed and deliberately unspecific, because unspecific is the only thing both sides can sign. A treaty position keeps the peace internally and says nothing externally, and it usually holds until the first year in which one side's numbers are clearly worse.
The third is the winner's erasure, which is less common and sometimes correct. The larger party simply imposes its brand and position wholesale. This can work, and works best when the acquisition was for capability rather than for market presence. It fails when the acquired business had the stronger position and the acquirer mistakes balance sheet size for brand equity. Plenty of forty million pound businesses have bought eight million pound businesses with better positions and quietly destroyed the thing they paid for.
What actually works is less comfortable than any of those, and it is this: decide what the merged business is for, from first principles, as though neither legacy company existed.
Not a compromise between the two. Not a selection of one. A position for the business that now exists, which is a business neither of you was.
That will look like disloyalty to somebody. It is the price. And it is far cheaper paid in month three than in year three, because everything you build in the meantime, the hires, the pitches, the pricing, the integrations, will have been built on a question you had not answered.
A few practical notes. Do the customer interviews across both client bases and do them before you decide, because the two sets of customers will describe you differently and the gap between them is the actual strategic problem. Expect the culture question to arrive disguised as a brand question, since people argue about logos when they are worried about jobs. And decide the naming and architecture question separately from the position, later, because deciding what it is called before deciding what it is guarantees you get both wrong.