ERP in the First 100 Days After an Acquisition - What to Decide Now and What Can Wait
Updated: 18 hours ago
The deal closes on a Friday. By Monday the sponsor wants a reporting package, the lender wants its covenant calculations, the value-creation plan wants purchasing savings, and the portfolio company's CFO is asking whether the business needs a new ERP system. On day ten the honest answer is almost always: not yet, but we need to know by day 100.
Systems are usually the slowest workstream in post-merger integration, and ERP is the slowest system. This guide is for private-equity operating partners and portfolio-company CFOs who have just bought a manufacturer or distributor. It covers what to settle about ERP after an acquisition, what can safely wait, and how to avoid the two expensive mistakes we see most often: starting a replacement before the facts are in, and deferring the decision until events make it for you. The short version: decide in the first 100 days, and replace on a plan.
Two ways the systems question goes wrong
The rushed replacement - A new leader arrives, the old system is blamed for everything, and a vendor demonstration is booked for week three. A contract is signed before anyone has written down how the business actually runs. The implementation then discovers the real requirements one change order at a time, the go-live date slips into the second year of the hold, and the program ends up needing a reset.
The indefinite deferral - The system goes on the year-two list. Meanwhile month-end takes two weeks, the first add-on runs on its own books, and the board package is assembled in spreadsheets by the one person who knows where every number comes from. When a support end date or the next add-on finally forces the question, there is no time left to answer it well.
A disciplined 100-day look costs far less than either, and it gives the board a decision it can explain to a buyer's diligence team at exit.
Days 1–30: stabilize and see
Nothing in the first month should depend on the long-term systems plan. The job is to make sure the business can report, pay and ship while you learn how it works.
Close and reporting - Map the chart of accounts to the sponsor's reporting format, and write down the month-end close as it really happens, spreadsheets included.
Access and controls - List who has administrator rights, who can change vendor bank details and who can post journal entries. Former owners, departed staff and outside resellers often still have access.
Key people - Name the one or two people who keep the current system running: the controller who knows the workarounds, the IT generalist who wrote the reports, the reseller who holds the admin password. Losing them is the biggest near-term systems risk, and a retention conversation is cheaper than a rescue.
Contracts and dates - Find the license renewals, the support end dates for older on-premise versions and the hosting agreements. In a carve-out, read the transition services agreement (TSA) closely: which systems the seller keeps running, for how long, and what an extension costs. A TSA deadline is one of the few things that should force a fast ERP decision.
Days 30–60: write down what the business actually does
Before anyone can judge a system, someone has to describe the work it must support, at a level a vendor could respond to and an evaluator could score.
The core processes - quote-to-cash, procure-to-pay, plan-to-produce or order-to-ship, inventory and warehouse, and record-to-report.
For a manufacturer - the modes of manufacturing (make-to-stock, make-to-order, engineer-to-order or a mix), how product costs are built, how the shop floor records labor and material, and the quality and traceability obligations customers impose.
For a distributor - the branch and warehouse network, pricing and rebate agreements, EDI trading partners, landed cost, and delivery and route management.
The hidden system - every custom report, integration, add-on and spreadsheet the business depends on. This inventory is where the true cost of any change is hiding.
Data condition - a quick look at the item, customer and vendor masters, and at bills of material and routings, shows how much cleanup any path will need.
None of this is wasted if the answer turns out to be "keep what we have." It becomes the requirements baseline for a selection, the scope of a consolidation project, or the checklist for the next add-on.
Days 60–90: decide the target state for ERP
For a platform company and its future add-ons there are three realistic answers.
Keep and consolidate - Each company stays on its current ERP, and a consolidated reporting layer sits above them. This fits when the companies operate independently, the systems are supportable, and the investment thesis does not depend on shared purchasing, inventory or customers. It is the least disruptive answer today and can become the most expensive one by the fourth add-on.
Absorb onto the platform's system - Add-ons move onto the platform company's ERP. This fits when that system is current, suits the way the add-ons work and can scale with the plan. The risk is forcing an engineer-to-order add-on into a system built for distribution, or the reverse.
Select a new platform for the group - This fits when neither system can carry the combined business through the hold period, with more sites, more legal entities or new channels. It is a selection program, not a software purchase, and it should start from the documentation built in days 30–60.
Five questions decide it: where the thesis expects synergies to come from; how long the hold is and what a buyer will look for at exit; how many add-ons are planned; how much change finance and operations can absorb alongside everything else in the value-creation plan; and how long the current systems can be supported.
Days 90–100: take a plan to the board
The board needs the decision, the reasons, the risks, and what it will take in people and time. It does not need a vendor quote yet.
If the answer is a new platform: a selection program of twelve to twenty weeks, timed around the business calendar so that it avoids a distributor's peak season and the year-end close. Here is how a selection program runs, week by week.
If the answer is keep and consolidate: the reporting layer, a common chart of accounts, and the trigger that would reopen the question, such as a third add-on or a support end date.
In either case: an executive sponsor at the portfolio company, usually the CFO or COO, with the operating partner holding the gate on scope and budget.
What can wait
Choosing a vendor. Before requirements exist, a demonstration shows you the vendor's best script, not your business.
Signing an implementation contract. Scope, data readiness and governance come first; that is the purpose of a decision check before you sign.
Harmonizing every process across the group. Standardize the chart of accounts and the reporting calendar first. Process harmonization follows the target-state decision.
Where an independent adviser helps
The first 100 days are the busiest of the hold, and the people who know the business are needed to run it. A small senior team that has done this before can produce the documentation and the options analysis in weeks while management keeps its attention on the plan. An adviser with no software to sell can also tell a board that the right answer is "not yet," which a vendor or implementation partner rarely will. And when the answer is a new system, the same people can run the ERP software selection and then stay on the client side through implementation.
Frequently asked questions
Should we replace ERP in the first 100 days after an acquisition? Rarely. Decide in the first 100 days and replace on a plan. The exception is a carve-out whose transition services agreement ends before a new system could be selected and implemented; then the selection has to start in the first weeks.
Do add-ons have to move onto the platform company's ERP? No. Many buy-and-build groups consolidate reporting first and move add-ons only when the value case for shared operations is clear.
Who should own the ERP decision at the portfolio company? The CFO or COO as executive sponsor, supported by the business-process owners, with the operating partner approving the target state and the budget.
How long does it take once the decision is made? A selection for a multi-site company runs twelve to twenty weeks. Implementation depends on scope and phasing; for a multi-site manufacturer or distributor it usually takes the better part of a year, and often longer.
If you have just closed on a manufacturer or distributor and the systems question is on your list, talk to John about your ERP program.
