AI agents for business finance: what they can and can't do
What AI agents can do in bookkeeping, close, collections and compliance today, where a person must stay in charge, and how to judge a product.
The short answer
A Treasury bill ladder splits your money across bills that mature at different times, so part of it comes back every few months and can be spent or reinvested. From the UK, the simplest version buys a 364-day bill every quarter for a year, then rolls each one as it matures. Using October 2026 stop rates and 10% Nigerian withholding tax, a ₦1,000,000 one-year bill would return about ₦142,000 net, before UK tax and before any currency move.
Why ladder at all
Putting everything into one 364-day bill gives you the highest rate on offer but locks it all up for a year and leaves you exposed to whatever rates are on the day it matures. A ladder trades a little of that for flexibility: money comes back at regular intervals, you reinvest at a spread of rates rather than one, and if you suddenly need naira for school fees or a family emergency, part of the ladder is never far from maturity.
For a UK-based saver there is one more reason. Each maturity is a natural decision point on currency: you can hold the naira, spend it in Nigeria, or convert to pounds, depending on what the exchange rate and your plans look like at that time.
How Nigerian T-bills work, briefly
Nigerian Treasury bills are issued at auction by the CBN for the DMO in three primary tenors: 91, 182 and 364 days. As at October 2026, Nairametrics reported auctions held on Wednesdays with settlement the next day. At the 7 October 2026 auction, stop rates were 15.50% (91 days), 15.80% (182 days) and 15.85% (364 days). Rates move with every auction; check the latest CBN result before you buy.
Direct bids at the primary auction go through the CBN’s system with a minimum of ₦50,001,000, according to the CBN notice reported by Nairametrics for the 29 July 2026 auction. Most individuals therefore buy through a bank or broker that pools orders, or in the secondary market, where minimums are set by each bank. For the Nigeria-side buying process, see how to buy Treasury bills in Nigeria and, for bidding from abroad, buying T-bills at the primary auction from the UK.
The worked example
Labelled example. Kemi in Leicester has naira savings and adds ₦1,000,000 every three months for a year. Each time, she buys a 364-day bill. The rate used for every rung is the 7 October 2026 stop rate of 15.85%, treated as simple interest on the amount invested to keep the arithmetic clear. Real bills are sold at a discount and repaid at face value, so your bank’s contract note will show slightly different figures.
| Rung | Bought | Matures | Interest (15.85% × 364/365) | Less 10% WHT | Net interest |
|---|---|---|---|---|---|
| 1 | Month 0 | Month 12 | ₦158,065.75 | ₦15,806.58 | ₦142,259.18 |
| 2 | Month 3 | Month 15 | ₦158,065.75 | ₦15,806.58 | ₦142,259.18 |
| 3 | Month 6 | Month 18 | ₦158,065.75 | ₦15,806.58 | ₦142,259.18 |
| 4 | Month 9 | Month 21 | ₦158,065.75 | ₦15,806.58 | ₦142,259.18 |
From month 12, one rung matures every quarter. Kemi rolls each ₦1,000,000 into a new 364-day bill at whatever the rate is then, and takes the net interest out, or adds it to the next rung. Four rungs of ₦1,000,000 give ₦4,000,000 working, and in this example ₦569,036.72 of net interest in the first full cycle (4 × ₦142,259.18).
A faster start using shorter tenors
If you have the whole sum at once, you can build the ladder on day one with the shorter primary tenors and roll each into 364 days at maturity. Same labelled assumptions, using the 7 October 2026 rates, on ₦1,000,000 each:
- 91 days at 15.50%: interest ₦38,643.84, WHT ₦3,864.38, net ₦34,779.45;
- 182 days at 15.80%: interest ₦78,783.56, WHT ₦7,878.36, net ₦70,905.21;
- 364 days at 15.85%: interest ₦158,065.75, WHT ₦15,806.58, net ₦142,259.18.
That gives you maturities at three, six and twelve months immediately. A nine-month gap can be filled with a bill of around 270 days bought in the secondary market, if your bank offers one.
Tax in Nigeria and in the UK
A November 2025 Mondaq summary reports a FIRS directive, dated 16 September 2025, requiring financial institutions to deduct 10% withholding tax on interest from short-term securities including Treasury bills. That is the deduction used above. In the UK, GOV.UK says UK residents normally pay UK tax on foreign income, including interest, usually through Self Assessment, with relief for foreign tax paid. Each rung’s interest is converted to pounds for UK reporting; check with HMRC or an adviser which tax year a maturity falls in. See UK tax on Treasury bill interest. This is information, not tax advice.
Risks a ladder does not remove
- Currency. Every naira you hold is exposed to the naira falling against the pound. A ladder spreads timing, not currency risk.
- Falling rates. Stop rates fell sharply after the September 2026 rate cut. If they keep falling, each rung rolls at a lower rate.
- Access. Getting out before maturity means selling in the secondary market at that day’s price, if your bank will buy it back.
- Paperwork. Keep every contract note and withholding tax record; you need them for HMRC.
To automate the rolling, see rolling over Nigerian T-bills automatically.
Where Pryme fits
A ladder runs on naira, and each maturity is a chance to decide whether to keep it in naira. A Pryme account holds naira and pounds side by side, so you can top up rungs in naira and convert only when you choose with Swap, which shows the rate first and the fee on its own line.
Questions people ask
What is a T-bill ladder?
Splitting money across Treasury bills that mature at different dates, so part comes back regularly and can be reinvested or spent.
Can I buy Nigerian Treasury bills from the UK?
Yes, usually through a Nigerian bank, broker or fund manager, paying in naira. Direct primary auction bids need ₦50,001,000 or more.
How much tax is taken from Nigerian T-bill interest?
A 2025 FIRS directive requires 10% withholding tax on T-bill interest. UK residents normally also report the interest to HMRC, with credit for the Nigerian tax.
What are Nigerian T-bill rates today?
As at October 2026 the 7 October auction gave 15.50% (91 days), 15.80% (182 days) and 15.85% (364 days). Check the latest CBN auction result for current rates.
Sources
- Nairametrics: DMO raises N968.47 billion as 364-day stop rate falls to 15.85%, 7 Oct 2026 · accessed Oct 2026
- Nairametrics: CBN offers N450 billion at second NTB auction of Q4, 14 Oct 2026 · accessed Oct 2026
- Nairametrics: CBN targets N700 billion in final Treasury bills auction for July 2026, 26 Jul 2026 · accessed Oct 2026
- Mondaq (Advocaat Law Practice): FIRS imposes 10% withholding tax on interest on short-term securities, 14 Nov 2025 · accessed Oct 2026
- GOV.UK: Tax on foreign income · accessed Oct 2026
- Nairametrics: NTB stop rates crash across tenors after CBN’s 350bps rate cut, 24 Sep 2026 · accessed Oct 2026
This article is general information, not financial, legal or tax advice. Products described are provided under the terms on this site and are subject to regulation and eligibility.