Nigerian tax periods before 2026 and straddling years
How a Nigerian business handles tax periods before 1 January 2026, why Achekam refuses a year that straddles that date, and how to keep the workings apart.
By Achekam · · 4 min read · For Running a business businesses in Nigeria
Take a Nigerian company with a June year end. Its financial year began on 1 July 2025, under the old tax laws, and ends on 30 June 2026, under the new ones. Half its trading happened before the Nigeria Tax Act 2025 commenced and half after. Which law governs its company tax for the year? And what happens when it asks its accounting software to compute it?
Many Nigerian businesses are in exactly this position, and many more still have open questions about 2025 and earlier years. This article explains the legal starting point, why Achekam refuses to compute those periods, what that refusal is telling you, and how to keep the old-law work properly separate from the new.
Earlier periods stay under the repealed laws
The Nigeria Tax Act 2025 commenced on 1 January 2026, and tax periods before that date stay under the repealed laws. The Act repealed a long list of older statutes, among them the Capital Gains Tax Act, the Companies Income Tax Act (CITA), the Personal Income Tax Act (PITA), the Petroleum Profits Tax Act, the Stamp Duties Act and the VAT Act.
So a VAT return for December 2025, a 2024 company tax computation, or an objection about an old assessment all turn on laws that no longer apply to new periods but still govern the old ones. The Federal Ministry of Information's notice that the Federal Government issued transition guidelines for the 2025 tax Acts is a starting point for how the changeover is meant to work. Read it with your adviser before you settle anything about a period that crosses the line.
Why Achekam holds no Nigerian rule before 2026
Achekam holds no Nigerian tax rule for periods before 1 January 2026, and it refuses to compute those periods. The old regime had its own rates, levies and reliefs, and the Development Levy that now applies to most companies at 4% of assessable profits replaced several separate earmarked levies. Computing past years would need a second rule book for all of that, and Achekam does not hold one. A refusal is less convenient than a guess, but it cannot produce a confident wrong answer.
Even for 2026 periods, nothing is computed until the rules are approved. Every Nigerian tax figure in Achekam's rule book was seeded "under review", and Achekam computes nothing from a figure until an Achekam platform administrator approves it. Once approved, Achekam's Revenue Service Centre computes company income tax with the Development Levy and the minimum-ETR check, VAT, withholding tax, capital gains and stamp duty, for periods on or after the start date.
Financial years that straddle 1 January 2026
Monthly taxes are simple: a VAT month falls wholly before or wholly after the change. Company tax is not, because a company's year can begin in 2025 and end in 2026.
In Achekam, company tax and levy rules resolve on the period's first day. A year that begins before 1 January 2026 therefore resolves to a date for which Achekam holds no rule, and the period is refused, even though most of it may fall in 2026.
The stakes in that year are real. From 1 January 2026, a small company pays 0% company income tax and every other company pays 30%, and the Development Levy applies to companies other than small and non-resident ones. How a year that began under the old regime is taxed is a question for the law and the transition guidance, applied by your adviser, not for a software default. How the new rates work once you are clear of the changeover is covered in Nigerian company income tax from 2026.
What the refusal tells you
When Achekam refuses a Nigerian period, it is telling you one of two things:
- The period starts before 1 January 2026. The work belongs under the repealed laws, outside Achekam.
- The rule is not yet approved. The period is in range, but the figure it needs is still under review.
Do not try to get round the first by changing the period's start date in Achekam. A computation that pretends the year began on 1 January would be tidy and wrong.
Working the old period with your adviser
- Confirm the exact start and end dates of the period in question.
- Ask your adviser which law and which rates apply to it, and how the transition guidance treats a straddling year.
- Prepare the computation outside Achekam, noting the source of every rate.
- Have a second person review it.
- File and pay through the channel the old period requires, and keep the receipt.
Nigeria's 2025 Acts also exist in more than one text, which can matter for the figures you apply; see the two texts of Nigeria's tax Acts.
Keeping the two sets of workings apart
For a business with periods on both sides of 1 January 2026, keep two clearly separated files:
| Old-law file | New-law file |
|---|---|
| Periods before 1 January 2026, and any year that straddles it | Periods beginning on or after 1 January 2026 |
| Computations prepared outside Achekam | Returns prepared, reviewed and approved in Achekam |
| Rates sourced from the repealed laws | Rates from Achekam's approved rule book |
| Label: "Worked outside Achekam: repealed law" | Normal Achekam records |
Never mix a figure from one into the other without a note saying where it came from. For a summary of what changed on 1 January 2026, read what Nigeria's 2025 tax Acts changed for businesses.
General guidance only, not advice on your own circumstances. Tax and payroll rules change: check the current position with the authority or your adviser.
