Learning how to integrate two accounting systems after a merger is less about software than about agreeing on what the numbers mean. When it works, the combined company has one chart of accounts, one close calendar and one set of opening balances before the first joint month-end. When it does not, each old system keeps its own version of the truth.

Decide what the combined books must answer before you touch either system

The first step is not technical. Before anyone opens the two systems side by side, the leadership team should write down the questions the combined books have to answer. Typical ones are simple: how much cash each entity holds, which customers owe money and for how long, what the monthly margin looks like by product or location, and what a lender or board will ask for next quarter. Each question points to a set of accounts, a reporting cadence and an owner.

This list matters because the two companies probably built their books for different purposes. One may have been organized around tax filing, the other around management reporting. A business run from spreadsheets may track projects, while a larger firm tracks departments. None of these choices is wrong on its own, but they rarely fit together unless someone decides which purpose comes first. A clear list of required outputs gives that decision a reference point.

Once the outputs are listed, compare them with what each system can produce today. Pull the last year of monthly reports from both companies and note which ones you can rebuild without manual work and which depend on a person who knows a workaround. That inventory often reveals a gap nobody had named. It also shows where old processes carried hidden weight, such as a weekly cash call that existed only because a former bookkeeper tracked payments in a notebook.

Keep this phase short and written down. A one-page memo listing the required outputs, the owner of each, and the systems that produce them now is enough to start. Tell the team that this memo is the standard for the rest of the project. Later debates about account names or report formats can then be settled against it, not against personal preference.

This is also where you decide who speaks for the finance function during the work. Some leaders name a single internal owner, some bring in outside help, and some split the job between a controller and an advisor. The right choice depends on how much judgment the project needs and how much time the internal team can free up. Writing the answer down now prevents the common situation where two people make conflicting decisions about the same account in the same week.

Gap one: the two charts of accounts describe the same business differently

The chart of accounts is the list of ledger accounts a company uses to classify transactions. Two charts can look similar at first glance and still disagree in ways that matter. One company may record software subscriptions under operating expenses, while the other splits them between technology and professional services. One may hold deferred revenue in a single account, while the other tracks it by contract. Those small differences change every report built on top of them.

Start with a mapping table. List every account in the company being absorbed and assign each one to an account in the surviving chart, a new account, or a sub-account that preserves history. The table should record the logic, not only the destination. A line that says "contractor fees map to professional services" is less useful than a note explaining that the old system netted reimbursed travel against revenue, so the mapping has to handle that case separately.

Intercompany accounts deserve special attention. When two entities in the same group charge each other for shared services, those balances must eliminate in consolidation. If one company records a shared payroll run as a receivable and the other records it as an expense, the combined statements will not balance unless someone maps both sides carefully. A short intercompany review before the first combined close catches most of these problems early.

Naming matters more than most teams expect. Account names that look identical can carry different rules. "Other income" in one company may include grant money, while in the other it captures gains on asset sales. Agree on definitions in writing and attach them to the account descriptions in the new chart. The people who read the reports later will rarely have access to the meeting where these choices were made.

A careful mapping also protects historical comparisons. Investors and lenders often want to see trends over several years, and those trends break if last year's revenue sits in a different category than this year's. Decide whether prior periods will be restated under the new chart or shown with a bridge that explains the difference. Either approach can be defended, but it must be consistent and disclosed. The depth of the mapping should also match the decision it supports. A company preparing for a sale needs more granularity than one that only wants clearer cash visibility.

Gap two: close calendars, cutoffs and revenue rules that do not match

The second gap sits in timing. Each company has a close calendar, a list of tasks and deadlines that turn transactions into a finished month. In a hypothetical case, one company closes in about six business days because bank reconciliations happen daily, while the other takes twice as long because accruals are reviewed only at quarter-end. When the two calendars meet, the team often finds that nobody owns the handoff between them, and the combined close stretches out.

Cutoff is the practical test. It is the rule that decides which transactions belong to which period. A purchase received on the last day of the month may be recorded as an expense, an accrual, or nothing at all, depending on policy. If the two companies used different thresholds for accruing supplier invoices, the first joint month will show a jump or a dip that has nothing to do with the business.

Revenue recognition is the hardest part of the timing gap. For companies that sell software, subscriptions, services bundled with products, or multi-year contracts, the standard matters. ASC 606 sets out the framework most U.S. companies use for revenue from contracts with customers, including how to identify performance obligations and when revenue is recognized. Two companies that read this framework differently can report the same contract in very different ways during the same quarter.

Do not try to fix every policy at once. Start with the policies that drive the largest balances or raise the most questions, such as deferred revenue, accrued liabilities, capitalized costs and bad debt reserves. For each one, write the rule the combined company will follow, the evidence needed to support it, and the person who reviews the entries each month. A policy that exists only in someone's head will not survive the first staff change.

Watch for timing changes that look like performance changes. If the new close takes more days, leaders may see late reports and assume the business is slipping. If a revenue policy shifts, margins may move even though sales did not. Before you compare results across the merger date, write a short note explaining the policy changes and estimate their effect where you can. Without that note, the board will read a timing effect as a business trend.

Gap three: opening balances, user access and controls that were never tested together

Opening balances are the figures that carry each account into the new system on the cutover date. They look simple, one number per account, but they are the point where two histories meet. If the cash balance in the new system differs from the bank statement, every later report inherits the error. Reconcile each balance to supporting evidence, such as bank statements, customer aging reports, fixed asset registers and payables listings, before you call the migration complete.

Access rights are the second part of this gap. In the old setup, one person may have approved payments, entered vendor bills and changed bank details, simply because the team was small. In a larger combined company, that arrangement becomes a control weakness. Review who can create vendors, post journal entries, release payments and edit reports. Remove access that existed only for the old system, and document why each remaining right is needed.

Approval thresholds need the same attention. The acquired company may have approved expenses informally above a certain amount, while the acquirer uses a formal matrix. Decide which matrix governs the combined entity, and test it with a few real transactions before go-live. A control that exists only on paper gives little protection. Keep evidence of approvals inside the system, so that an auditor or lender can trace who authorized what.

Build a simple audit trail from the first day. Export the migration log, the reconciliation workpapers and the list of manual adjustments made during cutover. These documents answer questions that often appear months later, typically during a financing or a sale. Companies that prepare them early are rarely caught off guard in due diligence, because the story of the numbers is already on file.

Plan for controls to be imperfect in the first quarter. Staff are learning new screens, and workarounds will appear. The goal is to see them early, record them, and remove them on a schedule. A monthly review of exceptions, with a named owner, is usually enough to keep problems visible without stalling the close. That review is not a substitute for an audit or a formal controls assessment, which depends on the company's size, industry and reporting obligations.

Choosing between keeping one system, combining both, or moving to a new platform

Once the mapping and the close logic are clear, the system decision becomes easier to judge. There are three common paths. The first keeps the larger company's system and migrates the smaller one into it. The second keeps both systems running for a period, with a consolidation layer on top. The third moves both companies to a new platform. The trade-off is different in each case, so the comparison should rest on your own criteria rather than on a vendor's demo.

Option What it keeps Main risk Often fits when

Keep the larger system and migrate the smaller company into it Existing reports and user habits Forces the smaller company's processes into a model that may not suit them One system already handles most of the transactions

Run both systems with a consolidation layer Daily operations at each company while the decision is pending Two sets of rules to maintain and more manual reconciliation The integration must be staged over a long period

Move both companies to a new platform A clean chart and fresh controls Heavier project load, data migration and retraining Both systems are weak, or the combined business needs features neither offers

Look at the criteria that matter for your company. Ask whether the system supports multi-entity reporting, intercompany eliminations, the revenue rules you chose, and the access controls you need. Ask how the vendor handles historical data, and whether the reports from your first step can be produced without custom work. Read the setup guides for the candidate systems, including QuickBooks, NetSuite and Sage Intacct, and confirm that the features you need appear in product documentation, not only in a sales presentation. Planning tools such as Adaptive Insights are often a separate decision from the ledger, so check whether budgeting and forecasting will live in the same platform or connect to it.

The right answer varies by segment. A startup with one entity and a simple revenue model may do well with a single cloud ledger, because its problems are mostly cash and speed. A life sciences company with grant accounting, lab costs and milestone revenue needs project-level tracking and clear cost allocation. A nonprofit reporting under ASC 958 must keep net assets with donor restrictions separate from those without, which changes both the chart and the reports. An agency with time-based billing needs work-in-progress tracking that many general ledgers handle poorly.

Decide with a scoring method, even a simple one. List the criteria, weight them according to the decisions your reports must support, and score each option against written evidence. Keep a note on what you could not verify. Leaders sometimes choose the platform that impressed them most in the demo, then discover a few months later that intercompany reporting requires a paid add-on. A plain scoring sheet makes those gaps visible before anything is signed.

Be honest about timing. A decision that waits until the year-end audit can push the integration into the busiest season. A decision made too quickly can lock the company into a structure it later wants to change. Set a date for the choice, and list the facts that would change it. That way the decision is recorded with its reasons, and the next person who asks why will find the answer on file.

A cutover sequence that keeps the first closes clean

The cutover is the moment the new structure goes live. It works best as a sequence in which each step depends on the one before. Skipping a step usually shows up later as a reconciliation problem that takes weeks to unwind. The steps below assume the chart, the policies and the system choice are already settled. Adjust the timing to fit your company, but keep the order.

Freeze the chart of accounts and publish the mapping table, with the logic for each line, before any data moves. Run a test migration into a sandbox, then reconcile trial balances, open invoices and bank balances against the source systems. Agree on the cutover date and a short freeze window in which no new entries are posted to the old systems except by the migration team. Load the opening balances, reconcile each one to supporting evidence, and get sign-off from the owner of each account. Run a parallel close for at least one full month, comparing old and new outputs line by line. Retire the old entry points once the parallel close matches, and keep read-only access for audit requests.

Each step has a reason. The sandbox run exposes data quality problems while they are still cheap to fix. The freeze window prevents a transaction from being posted to the old system after the balances have been copied. The parallel close is the most important step, because it is where differences in policy show up in real numbers. Many teams skip it to save time, then spend the next quarter explaining why the reports disagree.

Keep a cutover log with the time, the person and the result of each action. When a number looks wrong three months later, the log shows whether the problem came from the migration, a manual adjustment or a policy change. Without it, the team argues from memory, and the argument often ends with someone rebuilding a figure by hand.

Plan for a longer parallel period if the business has seasonal peaks, a pending financing or a sale on the horizon. A parallel close during a quiet month may not reveal the problems that appear during a busy quarter. Ask which periods will test the new setup most, and make sure at least one of them falls inside the parallel window or receives a specific review.

When the sequence is complete, write a short closing note for the file. List the systems in use, the owners of the chart, the policies changed during integration and the open items. This note is not a formal audit document, but it saves time for the next controller, the next auditor and the next lender who asks how the numbers were built.

Who does what during the work, and what the first 90 days look like

Integration involves several roles that are often blurred together. A bookkeeper records transactions and keeps the subledgers current. An accountant prepares statements and tax filings and may own the year-end. A controller owns the close, the internal controls and the accuracy of the ledger. A CFO sets financial strategy, the forecast and the story the numbers tell the board, investors and lenders. A fractional CFO fills the senior role for a set amount of time each month, without a full executive payroll.

The distinction matters when you choose help. A bookkeeper who is excellent at transaction entry may not design a revenue policy. An accountant may be strong on compliance and less interested in forecasting. A fractional CFO does not replace the controller who runs the daily close. In many companies the best arrangement is a controller or senior accountant running the close, with a fractional CFO deciding the policies, reviewing the integration plan and do i need a part-time CFO in Massachusetts presenting results to leadership.

Week to week, the work looks different depending on the stage. In the early weeks, a fractional CFO may spend most of the time with the CEO and the controller, reviewing the outputs memo, the mapping table and the cutover plan. Later the focus shifts to the close, the variance review and the forecast. Expect regular check-ins with the accountant about the tax effects of the merger and with the board, if one exists, about timing. Ask each provider to describe the usual cadence in writing before you sign anything.

The first ninety days usually follow a pattern. Early on, the team inventories systems, reports and policies, and agrees on the chart. The middle period covers the test migration, the cutover and the first parallel closes. The final stretch concentrates on the reporting package, a controls review and a clear handover of ownership. A fractional CFO may stay involved after that, but the internal team should be able to run the close without outside help. Measure progress against the written outputs list, not against how busy the calendar looks.

Some companies outgrow the fractional model during integration. If the combined business has several entities, a financing in progress, operations outside the United States and Canada, or a need for daily leadership on cash and hiring, a full-time CFO may be the better fit. Watch for the signals: decisions queue up waiting for the same person, the board asks for more time than the arrangement allows, or the work needs a presence a part-time model cannot provide. The move is a choice, and it should be made on the work, not on the title.

Checks to run before you call the integration finished

The integration is finished when the combined company can produce its key reports without manual rescue, and when someone outside the project can explain how the numbers were built. Before you close the project, run through the checks below. Each one is a question you can answer with a document, not with a feeling about how things went.

Every account in the new chart has a written definition, an owner and a link to the mapping table. The monthly close runs on the new calendar, with handoffs named and open items tracked. Opening balances reconcile to bank statements, receivable and payable listings, and fixed asset registers. User access matches current roles, and approval thresholds have been tested with recent transactions. The cutover log, the parallel close comparison and the closing note are filed where a lender or auditor can find them.

These checks are deliberately practical. They do i Need A part-time cfo in massachusetts not promise growth or guarantee that a financing, loan or sale will succeed. They confirm that the foundation is sound. A lender, investor or buyer will test that foundation, and due diligence teams tend to ask for exactly these documents.

Expect some open items to remain after the checks. A few reconciling differences that cannot be explained may be acceptable if they are small, recorded and assigned to an owner with a date. Leaving them unrecorded is the mistake. A short list of known issues, with a plan, is far more useful to a board than a report that claims everything is clean.

Recheck the setup after the first full quarter. Policies that looked settled may need adjustment once real transactions arrive, and new staff may find shortcuts that weaken controls. A quarterly review of the chart, the policies and the access list keeps the structure aligned with a business that is still changing. Put it on the calendar before the project closes, so it does not depend on someone remembering.

Finally, decide who owns the integrated accounting setup after the project team leaves. Name the controller or do i need a part-time CFO in Massachusetts finance lead, and give that person authority over changes to the chart and the policies. The decisions made during integration will keep affecting the numbers long after the project ends, and a clear owner keeps them from drifting.