A post-merger integration checklist is only useful if someone owns each line. Most checklists fail for the opposite reason: they list everything and assign nothing, so the urgent items get done and the important ones quietly drift. This article is for the CEO or owner of a company with ten to two hundred people that has just bought, merged with, or been bought by another business, often with a private equity owner, and who wants a plain list of what to check across the first year, area by area, with a named owner for each.
I was COO and then President of a public company that closed more than forty acquisitions, and I ran the integration on most of them. I am a lawyer by training. Now I write fixed-fee AI plans for CEOs of private-equity-backed and owner-led mid-market companies through 013 Labs. This is not legal, tax or accounting advice. Employment, contract, tax and data rules depend on the deal and where you operate, so ask your own advisers about anything that binds you.
How to use this list
One owner per line. Not a team, not a committee. A name.
Three columns. The item, the owner, and the date it will be checked. Anything without a date is a wish.
Start with the promises. Whatever was promised in the deal, to the new owner, the lender, the employees or the customers, comes first. The first hundred days after the deal covers that opening stretch, and the one-page checklist is the short version. This article covers the rest of the year.
People
Who reports to whom, written down. An organization chart for the combined company, shared, within the first weeks.
Pay and benefits. Every change to pay, benefits, titles or hours confirmed in writing to the people affected, with the dates. Surprises here cost people.
Key people. The handful of people the business cannot lose, named, with a plan for keeping each one.
One message. What employees are told, by whom, and when, so nobody hears it from a customer first.
Policies. Which handbook, which leave rules, which expense rules apply now, and from when.
Customers
The top customers, called personally. By someone senior, early, before a competitor calls them.
Contracts that change on a sale. Any customer contract with a change-of-control clause, found and handled.
One voice. Who customers call now, for what, and how pricing, terms and service will or will not change.
Money
One set of numbers. Which accounting system, which chart of accounts, and which monthly report the new owner sees, by what day of the month.
Who can pay. Bank accounts, signatories and payment approvals reviewed and reset. A request to change supplier or employee bank details always gets a phone call to a number you already had.
Cash. A weekly cash view for the first months, owned by one person.
The promises in numbers. Any earn-out, target or covenant in the deal, tracked on its own page.
Operations and systems
Which systems stay. For each overlapping system, a decision: keep, replace or merge, with an owner and a date. Not everything needs merging in the first year.
Access. Who has access to what, reviewed. Former owners, departed staff and old contractors removed.
Suppliers. Duplicate suppliers identified; contracts with change-of-control clauses handled.
Data and AI
What tools are in use, in both companies. Including the ones staff signed up for on their own.
One data rule. What never goes into an outside tool, the same for everyone in the combined company.
One owner. A named person who owns how the combined company uses AI. Who owns AI in a company sets out how to choose them.
No new projects before the basics. Where AI fits in post-merger integration covers where a tool genuinely helps after a deal, such as comparing contracts or reconciling customer lists, and where it is a distraction.
Legal and compliance
Licences, permits and insurance transferred or confirmed in the right entity's name.
Contracts assigned or re-signed where needed, with your counsel.
Records kept as the deal and the law require, with a named owner.
Reviewing the year
A monthly integration review. Thirty minutes: what moved, what is late, what changed.
A written close. At the end of the year, one page on what was integrated, what was left separate on purpose, and what is still open. A future buyer or lender will ask for exactly this. Does AI make my business worth more when I sell covers what they now ask about data and AI too.
Picture it going wrong
A company buys a competitor and puts "integration" on the agenda of every leadership meeting. Everyone agrees it matters; nobody owns a line. Six months later the two sales teams are still quoting different prices to the same customer, a former owner still has access to the bank, and the best engineer from the acquired company has quietly left. None of it was hard. All of it was nobody's job.
Mistakes that repeat
Lists with no owners. Merging every system in the first year. Telling employees too late. Forgetting change-of-control clauses. Leaving bank access unchanged. Starting new AI projects before anyone knows which tools are already in use.
Frequently asked questions
What should a post-merger integration checklist include?
People, customers, money, operations and systems, data and AI, and legal and compliance, with one named owner and a date for every line.
How long does post-merger integration take?
The urgent items take the first few months; most of the rest takes the first year. Some things, deliberately left separate, never merge.
What goes on a post-merger HR integration checklist?
The reporting structure, pay and benefits confirmed in writing, key people and how to keep them, one message to employees, and which policies apply from when.
What goes on a post-merger finance checklist?
One set of numbers and a monthly report, bank and payment access reset, a weekly cash view, and the deal's targets and covenants tracked on their own page.
Where does AI fit in integration?
After the basics: know which tools both companies use, set one data rule, name one owner, then use tools for jobs like comparing contracts or customer lists.
Is this legal or tax advice?
No. Ask your own advisers about employment, contracts, tax and data.
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