It was 9 July. Compensation mentioned, almost as an aside, that the merit increases approved in February were meant to be effective 1 January. Germany, the UK and the Netherlands never got the file. Forty-one employees, six months, an average uplift of 4.2 percent.
Nobody noticed, because every payslip in between looked like the one before it.
That is three problems, not one. You owe money. You owe corrected filings in at least one of those countries. And somebody has to decide that afternoon whether the July run absorbs it or you open something separate, because the German cutoff is Thursday.
The money is the easy part.
The first decision is whether the period is still open
If the period is open, this is boring work. Amend the input, recalculate, and one payslip carries July plus the January to June difference. Nothing has been filed, so nothing needs amending.
Once the period is closed and filed, two questions separate that most people keep together. The amount is arithmetic. How it is taxed in the period you pay it is a rule, and frequently not the rule that applied in January. Teams lose a week dropping six months of difference into the current run and finding the withholding looks nothing like six months of correctly withheld tax.
Cumulative countries absorb it. Per-period countries do not.
UK PAYE on a cumulative code recalculates against year-to-date pay every time you run it: free pay to date, tax due on pay to date, minus tax already paid. Pay six months of backdated increase in July and the income tax self-corrects, so by the following March the employee has paid what someone on that salary since 6 April would have paid. India gets there differently: the employer has to estimate the year’s salary and deduct proportionately, so a July increase simply resets the TDS across the remaining months.
National Insurance does not. NIC is assessed on each earnings period with no annual recalculation for an ordinary employee, which is why company directors get an annual earnings period and nobody else does. The retro lump lands in one monthly computation, part of it above the upper earnings limit, and that part attracts 2 percent instead of the main rate. The employee pays less NIC than six monthly payments would have produced, nothing trues it up, and it surfaces when someone reconciles.
Where each period is taxed on its own, the arithmetic runs the other way and the employee gets hurt. The Netherlands treats a backdated increase as a bijzondere beloning, withheld from the tabel bijzondere beloningen rather than the monthly table at a percentage set by the employee’s previous-year annual wage: for 2026, 35.75 percent up to 38,883 euro and 49.50 percent above 78,426 euro. A deliberate flat rate, rather than a monthly table treating one month’s spike as the new normal. Australia solves it by averaging, under Schedule 5.
The split is not a quirk of retro processing. It falls out of how each country sequences gross-to-net in the first place, and it is the reason one correction policy cannot cover a country list.
Germany splits on the calendar year. A Nachzahlung of regular wages for months in the current year is laufender Arbeitslohn and you recalculate those months. Once it relates to a prior calendar year and lands outside the first three weeks of the new year, it becomes a sonstiger Bezug taxed on the annual table.
The German trap is not tax. It is § 28g SGB IV: an omitted deduction of the employee’s social insurance contribution may only be made good at the next three wage or salary payments, and after that only where the omission was not the employer’s fault. Haufe’s worked example is a company car valuation error. The wage tax corrects back to January. The social insurance recovery reaches back three payroll periods. The employer pays the rest.
The amendment you actually have to file
Once a filing has gone in, the correction is itself a filing.
Check which side of a year boundary you are on before you start. In the UK the tax year that closed on 5 April 2026 is now an earlier year, which changes the form and not only the figure.
- United Kingdom. Current year, corrected year-to-date figures on the next regular FPS. Earlier years, an additional FPS with corrected year-to-date figures and late reporting reason H, which GOV.UK covers for tax years from 6 April 2020 through 5 April 2026. The Earlier Year Update is retired. HMRC also caps in-year clawback: you cannot recover more than the employee’s National Insurance due that month.
- United States. Form 941-X per affected quarter, using the adjustment process to credit a later return or the claim process to ask for a refund, then Forms W-2c with W-3c to the SSA. Overreported amounts run three years from the Form 941 filing date or two from payment, whichever is later. The limit that matters: the IRS instructions say 941-X cannot correct prior-year federal income tax withholding except for an administrative error, a transposition or maths error in what was actually withheld. Correcting a filing and correcting an employee’s tax year are different acts.
- India. A correction statement against Form 24Q: online through TRACES for challan, deductee and PAN changes, offline for deductor details and the Q4 Annexure II salary breakup. A revised Annexure II is what regenerates a corrected Form 16, so the job is not finished when TRACES accepts the statement. It is finished when the employee holds a certificate that matches it.
- Australia. A full file replacement where the last lodgment for that pay period was wrong and no later submission has touched those payees, one per 24 hours per pay period. Otherwise an update event carrying correct year-to-date values for all employees. Update events do not move your BAS figures, so W1 and W2 need fixing separately.
- Germany. A berichtigte Lohnsteuer-Anmeldung for each affected month, and expect the social insurance side to need its own correction where the contribution months move. § 41c EStG lets you correct withholding at the next payment, but only until the Lohnsteuerbescheinigung has been transmitted; after that you file the liability-relieving Anzeige with the Betriebsstättenfinanzamt and the tax office collects from the employee.
You paid net. The employee owes gross.
Overpayments are where this stops being a systems question.
Start with the arithmetic, because it sets the size of the ask. In the US, an employee repaying in the same calendar year repays net, and you back the wages out before the W-2 is issued. Repayment in a later year is gross, because the federal income tax withheld in the earlier year cannot be recovered by you at all. Social security and Medicare come back through 941-X and W-2c; the income tax is the employee’s to claim. A 6,000 dollar overpayment found in February is a 6,000 dollar conversation, not a 4,200 dollar one.
Then the right to take it, which is narrower than people assume. Section 13 of the Employment Rights Act 1996 bars any deduction from wages unless statute requires it, a relevant contract provision the worker already has in writing authorises it, or the worker has previously agreed in writing. Section 14(1)(a) excepts deductions reimbursing an overpayment of wages, which removes the statutory unlawful-deduction route. It does not settle whether the recovery is right in amount or lawful in contract.
Germany runs it through unjust enrichment under § 812 BGB, and the employee has a real defence. Under § 818(3) BGB, if the money is gone, spent in good faith on ordinary living costs, the enrichment is gone with it, and German courts presume disenrichment for lower and middle income employees where the overpayment is under roughly 10 percent of regular income. § 819 BGB removes the defence if the employee knew.
The Netherlands allows set-off only inside the closed list in article 7:632 BW, which does include wages paid in excess, and never against pay protected from attachment. France treats it as an indu under article 1302-1 of the Civil Code, caps the monthly deduction at 10 percent of net salary due absent written agreement, and allows three years under article L3245-1 of the Labour Code.
All of it lands in the same place: a signed repayment agreement stating the gross figure, the schedule, the tax year treatment and what happens on termination. Not a silent adjustment on the next payslip.
When the deductions are larger than the pay
A correction can produce a payslip where deductions exceed gross. A payroll system should never emit a negative net. Cut voluntary deductions first, then carry the shortfall forward as arrears with a visible balance, in a priority order you set in advance, not one the software picked.
Statutory limits sit on top. US federal garnishment law caps ordinary creditor garnishments at 25 percent of disposable earnings, or the amount above 30 times the federal minimum wage, and support orders at 50 or 60 percent plus 5 percent where arrears exceed 12 weeks. A US Wage and Hour opinion letter treats an overpayment as an advance of wages, so the FLSA permits recovering the principal even below minimum wage, though not fees or interest. States override: New York caps overpayment recovery at 12.5 percent of gross wages per pay period, and only for a mathematical or clerical error.
Keep the original number on the record
Every correction has to point back at the transaction it corrects, and the original figure has to stay visible. A system that overwrites it removes your only means of explaining anything. The employee asks why July is 3,400 euro higher and you can produce a total but not a derivation. The auditor asks who changed the salary and when, and you can show today’s value. The tax authority asks why the amended Lohnsteuer-Anmeldung differs from the original, and the original is gone.
HR Blizz was built the other way. Corrections run as their own controlled off-cycle run and merge back into the period without breaking the trail, and the 30-column audit trail carries old value, new value and source for every change by every user.
Before the next one
Prevention is unglamorous. A master data cutoff that actually locks, so late changes queue for the next period instead of arriving mid-calculation. Effective-dated changes in the HCM, keyed with the real effective date. And a retro report read every period, listing every change dated into a closed period, before you calculate rather than after.
Then write down what you cannot decide in the moment. The threshold above which a correction becomes an off-cycle run. Who signs one off in each country. The gross-or-net rule per country, decided once. A repayment agreement template your employment counsel has reviewed. And a correction register, so the tenth this year is not the first anybody has thought about.
The backdated increase will happen again. It should cost you an afternoon.
The amendment and recovery rules described above are general information, not legal advice; any specific case turns on the contract and the jurisdiction.
FAQ
Q: Should a retroactive pay correction go in the current period or run off-cycle?
If the period is still open, amend the input and recalculate, so one payslip carries both the current period and the retro difference. If the period is closed and the statutory return has been filed, the correction becomes an amendment, and an off-cycle run keeps it separate from the next regular cycle while still merging back into the period’s records.
Q: How do you correct a payroll error in an earlier UK tax year now the Earlier Year Update has been withdrawn?
GOV.UK guidance covers tax years from 6 April 2020 through 5 April 2026 by sending an additional Full Payment Submission with corrected year-to-date figures, flagged with late reporting reason H. Current-year errors are fixed by updating year-to-date figures on the next regular FPS.
Q: Does an employee repay an overpayment gross or net?
In the United States it depends on the calendar year. Repayment in the same year is net, because the wages can be backed out before the W-2 is issued. Repayment in a later year is gross, because the employer cannot recover federal income tax withheld in a prior year through Form 941-X except for administrative errors; the employee claims it on their own return.
Q: Can an employer simply deduct an overpayment from the next payslip?
Rarely without paperwork. Section 14(1)(a) of the UK Employment Rights Act 1996 excepts overpayment recovery from the statutory unlawful-deduction rules but does not settle the contractual position; Germany allows an unjust enrichment claim under § 812 BGB subject to the employee’s disenrichment defence; the Netherlands permits set-off only within article 7:632 BW and never against protected pay; France caps the monthly deduction at 10 percent of net salary without written agreement. A signed repayment agreement is the practical route in all of them.