When books changed after taxes were filed, first measure how much the change moves taxable income and which return lines it touches. Then tell the preparer in writing, with the before and after figures. The preparer decides whether to amend the filed return or carry a correction into the current year. Last, lock the filed year.
Why do books change after taxes were filed?
Books change after filing for a handful of ordinary reasons. A late statement arrives for an account nobody knew about. A reconciliation for the new year exposes a duplicate entry from December. A client finally explains a deposit. Or someone edits a prior-year transaction by accident, because the accounting software let them.
The causes fall into two groups, and the group matters for what happens next.
Corrections of real errors
These are changes that make the filed books more accurate:
- A missing month of statements turns up, with income or expenses that were never recorded.
- A transaction was entered twice, often once from a bank feed and once from an imported file.
- A deposit coded as a sale turns out to be a loan or an owner contribution, or the reverse.
- A vendor's payments were coded to the wrong account, changing a line on the return.
Changes that should not have happened
These are edits to a closed year that nobody intended:
- A team member recategorized a vendor's history and the change swept back into last year.
- Someone reconciled a new month and accidentally cleared or deleted an old transaction.
- An import of opening balances landed in the prior year instead of the new one.
The second group usually means undoing the edit, not telling the IRS anything. The first group may mean the filed return is wrong. Either way, the first step is to find out exactly what moved.
Sizing a change to books for a filed tax year
Sizing the change means comparing the filed year's figures before and after, line by line, and working out how much taxable income moved. A change inside one category, or between two expense accounts on the same return line, may not move the return at all. Missed income or a duplicate expense moves it dollar for dollar.
Start by reproducing what was filed. Most practices keep the trial balance or profit and loss sent to the preparer. Run the same report for the same year now and compare. Every difference needs an explanation: which transactions changed, when and why.
Then sort each difference by its effect:
- No effect on the return, such as moving a charge between two accounts that map to the same line.
- A change between return lines, such as moving an amount from supplies to meals, which changes how much is deductible if the categories are treated differently. Meals are the classic case; meals deduction records explains what those lines need to show.
- A change to taxable income, such as missed income, a removed duplicate expense or a reclassified owner draw.
Total the third group. That figure, along with any change in the second group, is the number the preparer needs. The bookkeeper should not decide whether it is "small enough to ignore." That judgment belongs to the preparer and the client.
Telling the preparer the filed-year books changed
The preparer should hear about a change to filed-year books as soon as it is confirmed, in writing, with the before and after figures. A short email with the comparison attached is enough. Waiting until the next tax season leaves less time if an amended return is needed, and it can change the current year's work too.
A useful message answers five questions:
- Which year and which entity the change affects.
- What changed, in one or two sentences.
- The figures: the filed amount, the corrected amount and the difference for each affected line.
- Why it changed: the late statement, the duplicate, the client's explanation.
- What the bookkeeper has done so far, such as undoing an accidental edit or holding the correction until the preparer decides.
Attach the evidence. If that means copies of bank statements, send only what is needed and remove details the preparer does not need; handling personal information on bank statements covers what to mask before a statement leaves the practice.
The usual path for sending year-end figures applies here too. If the practice already has a standard package for the preparer, follow the same format for the correction, as described in the bookkeeping handoff to a tax preparer.
Fix it in this year's books or amend the filed return?
Whether to amend the filed return or fix the error in the current year is a tax decision for the preparer, but the bookkeeper's analysis frames it. The preparer weighs the size of the change, whether it changes tax owed or credits, the time limits and the type of return. The bookkeeper supplies the numbers and the cause.
For individual returns, the IRS page on filing an amended return lists changes in filing status, income, deductions, credits, dependents or tax liability as reasons to amend, using Form 1040-X. It also notes a time limit for refund claims: generally within three years of filing the original return or two years after paying the tax, whichever is later.
Partnerships work differently. The IRS instructions for Form 1065 describe an administrative adjustment request for partnerships under the centralized audit regime, alongside amended returns for others. Which applies to a given partnership is the preparer's call.
The decision table below gives example changes and the step that usually follows. It is an illustration for discussion with the preparer, not a rule.
| Example change | Example size | Effect on taxable income | Usual next step |
|---|---|---|---|
| Supplies moved to office expense, same return line | 840.00 | None | Correct the books, note it, no return change |
| Supplies moved to meals | 1,200.00 | Can change the deductible amount | Send to the preparer to judge |
| Missed month of customer deposits | 6,400.00 | Income understated | Send to the preparer, amendment likely discussed |
| Duplicate expense from a bank feed and an import | 2,150.00 | Expenses overstated | Send to the preparer, amendment likely discussed |
| Owner draw coded as contract labor | 3,000.00 | Expenses overstated, 1099 list affected | Send to the preparer, check the 1099s filed |
| Accidental edit to a closed month | Any | None once undone | Restore the original entry, lock the year |
The fifth row shows how one error can touch more than one filing. A draw coded as contract labor may have produced a 1099 for a person who was never a contractor. Raise both issues in the same message.
Closing date locks for filed tax years
A closing date lock stops anyone from changing transactions on or before a set date without a password or a warning. Set it as soon as a year's return is filed, and change it only when a correction has been agreed with the preparer. Most accounting systems offer one.
The lock prevents the second group of changes, the accidental ones. It does not stop a deliberate correction; it makes the correction a conscious act. When a change is needed, the practice owner or a senior bookkeeper lifts the lock, makes the change and resets it the same day.
A few habits make the lock work:
- Set it on the day the return is filed, not at the next year end.
- Limit who can override it. One or two people per practice is enough.
- Check the audit log after any override, to confirm only the intended entries moved.
- Rerun the filed-year report after a correction and save it next to the original.
Bank rules and bulk recategorization tools are the usual way closed years change by accident. A lock protects those years even when a rule is applied to a vendor's entire history.
Filed-year book changes that need no amended return
Many changes to filed-year books need no amended return. A move between accounts that map to the same return line, an accidental edit that is undone, a better description on a transaction or a rounding difference all leave the filed figures standing. The books are corrected, the change is noted and the return stays as filed.
Some changes are fixed going forward instead. The preparer may decide that a small error is best corrected in the current year, for example by adjusting an opening balance. In that case the bookkeeper records the adjustment in the current year, with a memo that points back to the filed year, and leaves the filed year's figures as they were reported.
What should not happen is a silent fix. A bookkeeper who corrects last year's books without telling anyone creates a gap between the books and the return. Next year's preparer will find that the opening equity does not match the prior return, and the explanation will be harder to reconstruct a year later.
A change memo for the filed-year client file
A change memo records what changed in a filed year, why, who agreed the next step and what was done. It takes five minutes to write and saves hours when the same question comes up in a later year or an IRS letter arrives. Keep it in the client's file for that tax year.
A template:
Change memo: [Client], tax year [year]
Date found: [date]. Found by: [name].
What changed: [one or two sentences].
Figures: filed [amount], corrected [amount], difference [amount], affected lines [list].
Cause: [late statement / duplicate / client explanation / accidental edit].
Preparer told: [date, how]. Preparer decision: [no change / current-year adjustment / amended return].
Books updated: [date], lock reset: [date].
Attach the before and after reports and the email to the preparer. With the memo on file, anyone at the practice can answer the client's or preparer's questions about the year without retracing the work.
Late statements are the most common cause of a filed year moving. AutoBankConvert converts statements as they arrive and checks each one against its opening and closing balances, which makes a missing month easier to spot before the return is filed.