OMO Bills vs T-Bills in Nigeria: How They Work and How They Are Taxed
Suggested meta description: A plain-language comparison of OMO Bills and Treasury Bills in Nigeria, covering how each works, how to invest, and the tax treatment under current NRS guidance.
Businesses and individuals with surplus cash often ask the same question: where can it be held for a few months without tying it up for years? Two instruments come up most often, Treasury Bills (T-Bills) and Open Market Operation (OMO) Bills. Both are short-term, discount-based government-related securities, but they differ in who issues them, who can buy them, and how the interest is taxed.
This article explains both and sets out the tax position. It also shows why the tax side deserves as much attention as the yield.
This article is for general information. It is not investment or tax advice, and it does not recommend any product.
What Are T-Bills?
Treasury Bills are short-term debt securities issued by the Federal Government of Nigeria. They are typically offered at auction with tenors of 91, 182 and 364 days.
How they work:
- You buy the bill at a discount to its face value.
- At maturity, you receive the full face value.
- The difference between the two is your interest.
If you buy a ₦1,000,000 bill at a discount and it matures at face value, the gap is your return. No coupon is paid along the way.
What Are OMO Bills?
OMO Bills are issued by the Central Bank of Nigeria (CBN) as part of its liquidity management. The CBN uses them to adjust the amount of money circulating in the financial system. They also work on a discount basis and generally carry tenors of under one year.
Access has historically been narrower than for T-Bills. Participation has largely been through banks, institutional investors and other eligible participants, so individuals and smaller businesses often reach OMO Bills through their bank or a licensed broker. Eligibility rules can change, so confirm current requirements with the CBN or your dealing institution.
Side-by-Side Comparison
| Feature | T-Bills | OMO Bills |
|---|---|---|
| Issuer | Federal Government (via the DMO/CBN auction process) | Central Bank of Nigeria |
| Purpose | Government short-term funding | Monetary policy and liquidity management |
| Typical tenors | 91, 182, 364 days | Generally under one year |
| Pricing | Discount to face value | Discount to face value |
| Access | Broader, through banks and licensed dealers | Historically narrower; check current eligibility |
| Interest tax treatment | See below | See below |
Step-by-Step: How to Invest
The exact process depends on the institution you use. The general path looks like this:
- Define your purpose and time horizon. Decide how much you can set aside and when you will need the funds.
- Confirm your tax records are in order. Have your Tax Identification Number (TIN) and, for businesses, your CAC registration documents ready.
- Choose a licensed channel. This can be a commercial bank, a licensed stockbroking firm, or a registered dealer.
- Open or update your investment account, including a CSCS account where required, and complete the KYC process.
- Place your order. For T-Bills, this is done ahead of the auction or through the secondary market. For OMO Bills, it is usually through your bank or dealer.
- Review the confirmation. Check the tenor, the discount rate, the maturity date and the amount payable.
- Keep records. Retain the contract note, and for any tax deducted, keep the withholding tax (WHT) credit note for your filings.
Why This Matters to Taxpayers
Interest from these instruments is income, and the way it is taxed affects the net return. The policy has also moved in recent years, so past assumptions may no longer hold.
For a short time, government securities interest was broadly exempt under the Companies Income Tax (Exemption of Bonds and Short Term Government Securities) Order, which took effect in 2012 for ten years. That order lapsed in 2022, and afterwards only FGN Bonds continued to be exempt. andersen
Tax Implications: What the NRS Has Communicated
The Nigeria Revenue Service (NRS) is the successor to the Federal Inland Revenue Service. The FIRS was renamed the NRS following the Nigeria Revenue Service (Establishment) Act, 2025. The main reference points are: Wikipedia
- The October 2025 directive. On 28 October 2025, the tax authority directed banks, discount houses and stockbrokers to deduct 10% withholding tax on interest from short-term securities, with remittance by the 21st of the following month. The directive was issued under the FIRS name and is now administered by the NRS. mondaq
- Which instruments are covered. Commentary on the directive lists treasury bills among the covered instruments and notes that FGN bonds and CBN OMO bills are outside the deduction. Because directives can be clarified or amended, please confirm the current position with the NRS or a tax adviser before relying on it. mondaq
- The legal framework. The Nigeria Tax Act, 2025 treats income from government or corporate securities and discounts as part of taxable interest. The Nigeria Tax Administration Act, 2025 governs filing, payment, penalties and interest. africacheck
Practical points on the tax:
- WHT deducted at source is generally not the end of the matter. For companies, it can usually be claimed as a credit against tax payable, provided you hold the credit note.
- Individuals should confirm whether the deduction settles their obligation or whether the income must still be reported in their annual return.
- Where a security falls outside the WHT directive, the income may still need to be reported and assessed. Non-deduction is not the same as non-taxable.
Why Tax Compliance Matters
Compliance protects a business in practical ways:
- Late payment costs have been revised. From 1 October 2026, interest on overdue naira taxes is calculated at the CBN Monetary Policy Rate plus one percentage point, not below the 364-day Treasury Bill yield, and the NRS is to publish the applicable monthly rates. The 10% late-payment penalty remains. lawyard
- Records support your position. Credit notes and contract notes are the evidence behind any claim.
- Access to services. Tax clearance is often needed for contracts, licences and bank facilities.
- Sound governance. Accurate returns support audits, financing and due diligence.
Why Businesses Often Engage a Professional Tax Firm
Nigeria's tax framework has changed considerably since 2025. Businesses commonly work with a qualified professional for reasons such as these:
- Interpretation. Directives, regulations and Acts interact, and their effective dates differ.
- Fewer filing errors. Wrong tax periods, mismatched WHT credits and incorrect returns can lead to penalties and queries.
- Credit recovery. A professional can help reconcile WHT credit notes against filings so eligible credits are claimed.
- Planning. Timing and structuring of investments can be reviewed alongside cash-flow and tax positions.
- Representation. A professional can respond to NRS queries and correspondence on your behalf.
- Professional standards. Members of the Institute of Chartered Accountants of Nigeria (ICAN) work within its code of ethics and practice requirements.
Tips on Tax Credits and Opportunities
These items are drawn from the 2025 reform framework. Eligibility depends on your facts, so verify them for your own situation.
- Keep every WHT credit note. Reconcile them at least quarterly against your ledger and filings.
- Review small-company status. Companies with turnover of ₦100 million or less and fixed assets of ₦250 million or less are exempt from company income tax, capital gains tax and the new development levy. Filing obligations can still apply, so a NIL or routine return should not be skipped. Substack
- Understand the Economic Development Incentive. It replaces Pioneer Status with a 5% annual tax credit on qualifying capital expenditure for five years, with unused credits rolling over for a further five. Substack
- For individuals, income of ₦800,000 or less is now tax-free under the progressive personal income tax bands. Substack
- Match investment maturities to tax due dates so cash is available when liabilities fall due.
Relevant Tax Laws at a Glance
- Nigeria Tax Act, 2025 (charging and computation)
- Nigeria Tax Administration Act, 2025 (filing, penalties, interest)
- Nigeria Revenue Service (Establishment) Act, 2025
- Deduction of Tax at Source (Withholding) Regulations, 2024
- Companies Income Tax (Exemption of Bonds and Short Term Government Securities) Order, 2011 (lapsed in 2022)
Where to Get Further Assistance
For questions on how short-term investment income should be treated in your returns, you may contact US & CO. (Chartered Accountant), Lagos, Nigeria:
- WhatsApp: 08056219998
- Email: info@usc.com.ng
- Website: https://www.usc.com.ng
Frequently Asked Questions
1. What is the main difference between OMO Bills and T-Bills?
T-Bills are issued by the Federal Government to fund its short-term needs. OMO Bills are issued by the CBN to manage liquidity. Their access routes and tax treatment can differ.
2. Is interest on T-Bills taxable in Nigeria?
Under the NRS directive of 28 October 2025, a 10% withholding tax applies to interest on treasury bills, deducted by the paying institution. Confirm the current position before you invest.
3. Is interest on OMO Bills taxed?
Published commentary on the directive indicates that OMO Bills fall outside the WHT deduction. That does not automatically remove reporting duties, so confirm with a tax adviser.
4. Can the WHT deducted be recovered?
Where the deduction is treated as an advance payment, companies can usually claim it against their tax liability using the credit note. Keep the note and reconcile it to your return.
5. Does an individual need to file a return on this income?
It depends on the individual's overall income and the treatment of the deduction. A tax professional can confirm this against your records.
6. What happens if I file or pay late?
Interest and a 10% penalty can apply. The NRS publishes the applicable monthly interest rates, and it retains discretion to waive penalties or interest where sufficient cause is shown.
7. Who should review my investment and tax position?
A qualified professional such as an ICAN member can review your records and filings together.
Sources referenced: NRS/FIRS directive of 28 October 2025; Nigeria Tax Act, 2025; Nigeria Tax Administration Act, 2025; Nigeria Revenue Service (Establishment) Act, 2025. Tax rules change, so verify current provisions on the NRS website before acting
