Why Closing the Month Correctly Protects Your Tax Return

We recently onboarded a new pharmacy client and reviewed their 2025 books as part of that process. Every payroll run in QuickBooks Online generates a payroll journal entry that needs to be matched to the bank transaction that clears the account. If the bank transaction gets posted as a new expense instead of matched, the same payroll cost gets recorded twice, once through the payroll entry into wages, and a second time through the bank feed into whatever account the posting defaults to.

That is what had been happening to this client, month after month, and nobody caught it because the books were never formally closed and reviewed. The duplicate charges landed in the QuickBooks fees expense account, where they built up steadily over the year until that account no longer bore any resemblance to what QuickBooks and payroll subscriptions actually cost. Our in-house CPA confirmed the mechanism by reversing one month's reconciliation and re-matching the transaction. The cost moved out of QuickBooks fees and stayed, correctly and only once, in wages.

By the time we found it, the client's 2025 return had already been filed by their previous CPA, built directly from those overstated books. Payroll expenses were overstated, which meant income was understated, which meant the return was wrong. We are amending it now, both to correct this and to claim an R&D credit the client was also missing.

This is the part people miss about bookkeeping. It is not paperwork you do to stay organized. It is the source data for your tax return. Your CPA does not independently verify every transaction in your books. They build your return from what is already there. If the books are wrong, the return is wrong, and nobody catches it until something forces a second look.

Why categorization is the real starting point

Every number on a tax return traces back to how a transaction was categorized in QuickBooks Online. A supply purchase coded as an expense instead of inventory changes cost of goods sold. A loan payment coded as an expense instead of a liability reduction changes net income. None of these mistakes are visible from the outside. They move numbers in the wrong direction, without anyone noticing, until someone actually looks.

That is what closing the month is for. It is the point where someone reviews what happened financially over the past 30 days, confirms transactions are categorized correctly, reconciles the accounts against the bank and credit card statements, and locks the period once it is accurate. Once a month is closed and reviewed, you know the numbers in it are real. Nothing should change in a closed month without someone deliberately reopening it.

Skip that step and errors do not go away. They sit in the books, sometimes for months, and they carry forward into every financial statement and every tax filing built on top of them. A financial statement pulled from an unreviewed month is not actually telling you how the business performed. It is telling you how the transactions happened to get entered.

It does not matter whether you do this yourself, use an outside bookkeeper, or work with us. The review and close step has to happen before those numbers become a tax return. The question is not whether your books exist. It is whether anyone has actually confirmed they are correct before they get used for something that matters.

Where this fits with your tax plan

We have clients who prefer to keep their existing outside bookkeeper rather than move that work to us. That is fine. In those cases, Jessica reviews the books at a high level, closes the month, and prepares the financial statements herself before anything gets handed off for tax planning. That gives the client a second set of eyes confirming the numbers are accurate, and it keeps the books coordinated with the tax plan instead of the two operating separately.

A bookkeeper and a tax preparer who never talk to each other is one of the more common gaps we see. The bookkeeper closes out the year with whatever is in the file, and the tax preparer builds the return from whatever gets handed over, without either one confirming the numbers are right. A duplicate payroll expense, a purchase coded to the wrong account, a reconciliation that never happened, any of these can sit unnoticed through an entire filing season.

If you are not sure whether last month is actually closed and reviewed yet, or if your bookkeeper and your tax preparer are two people who never talk to each other, that is worth checking before those numbers become part of your return.

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If you have questions about this topic, speak with your CPA or accountant. And if you need guidance or a second opinion, you’re always welcome to contact us.