Regardless of how well the financials, numbers, products, etc. fit together, if you cannot successfully merge the people and culture during an integration it cannot be a success. Companies are more than just their products, they are the years of knowledge and the processes employees have learned.
Can an integration be called successful and complete if the people and culture are not meshing well together between the target and buyer?
This is a question I often wonder and from my HR perspective, I would not say it is a success. That being said, it is very difficult to support our statement as it remains qualitative and I have yet to find the right way to quantify in dollar amount the KPIs put in place that are sometimes not to the standards established.
As much as there is an emphasis on the people topics during the DD process and flags raised, it is still very hard to get the full attention on the success of an integration in the post-merger state.
I believe it is important to note that an integration can have different degrees of “integration”. If a private equity fund acquires two companies in the same sector but with different focuses on market segments, it could decide to keep its operations separate but try to implement the best practices seen in one of them in the other, “parenting” both and not merging their people and culture. If the objective is to have a more profound integration, I agree with you that to call it a successfull integration, a culture must prevail or a new one should be created for the NewCo.