91 vs 182 vs 364-day T-bills: which pays more?
Updated with the auction for bills issued 12 Oct 2026 · 6 min read
Kenya's Treasury bills come in three lengths: 91 days, 182 days and 364 days. The Central Bank of Kenya (CBK) sells all three at an auction every Thursday, and each needs at least KSh 50,000 face value. The longer bill usually pays more. Usually, not always. And the rate is only part of the choice.
This week's rates
| Bill | Rate before tax | After 15% tax |
|---|---|---|
| 91-day | 8.76% | 7.42% |
| 182-day | 8.87% | 7.49% |
| 364-day | 9.04% | 7.58% |
Rates from the auction for bills issued on 12 Oct 2026. After-tax rates use the same method as our T-bill calculator. See the full weekly figures in T-bill rates this week.
Why longer bills usually pay more
Lock your money away for a year and you give something up. You can't use it, and if rates rise you're stuck at the old rate. So investors expect extra pay for the longer bill. When rates rise from the 91-day to the 364-day bill, the line joining them (the yield curve) slopes upwards. That's normal.
The curve can also be flat, or even upside down (inverted). This happens when the market expects rates to fall, or when the government needs short-term cash and pays up for it.
2026 shows both. At the earliest auction in our records (bills issued 19 Jan 2026), the 364-day bill paid 9.20% and the 91-day bill 7.70%: a wide gap. In the first half of the year the 364-day rate slid to 8.27% (13 Apr 2026), and the 91-day rate to 7.40% (6 Apr 2026). The 91-day rate then climbed fast from late April. In May and June 2026, the 91-day bill briefly paid more than the 182-day bill. By mid-year, the extra pay for locking money away for a year had shrunk to a fraction of a percentage point. See every auction in the T-bill rates history.
Rolling a 91-day bill four times vs one 364-day bill
Four 91-day bills back to back cover 364 days. Rolling has two pluses. Your interest is reinvested every three months, so it compounds. And your money comes back four times, so you can change course.
It also has costs:
- Reinvestment risk, both ways. The next 91-day rate could be higher or lower. If rates fall, the 364-day bill would have locked in more. If rates rise, rolling wins.
- Idle money. When a bill matures, the money lands in your bank account and earns nothing until you buy the next bill at a later auction. A few idle days, four times a year, chip away at your return.
- Effort. Four bids instead of one.
The 364-day bill has its own reinvestment risk. If rates jump next month, your money is tied up at the lower rate for a year.
A rule of thumb: when the 364-day rate is well above the 91-day rate, one long bill keeps that extra pay. When the two are close, rolling the short bill earns about the same and keeps you flexible.
Getting your money out early
T-bills aren't traded on the Nairobi Securities Exchange. The main way out before maturity is to ask the CBK to rediscount (buy back) the bill. The CBK calls this a last resort and charges a penalty rate, so you get back less than you'd expect. In practice, pick a bill that matures before you need the money. For cash you can reach any day, a money market fund is a better fit.
Worked example: KSh 100,000 face value
| 91-day | 182-day | 364-day | |
|---|---|---|---|
| You pay (price + tax) | KSh 98,183 | KSh 96,398 | KSh 92,974 |
| Interest after tax | KSh 1,817 | KSh 3,602 | KSh 7,026 |
| Yearly return after tax | 7.42% | 7.49% | 7.58% |
| Money back in | 3 months | 6 months | 12 months |
You receive KSh 100,000 at maturity in each case. The 91-day bill pays the least interest because it lasts a quarter of the time.
Now roll the 91-day bill four times at today's rate, reinvesting everything. Over the year that works out at about 7.61% after tax, against 7.58% for one 364-day bill. That assumes the 91-day rate stays put for a year and your money is never idle. Neither is likely. Try your own figures in the T-bill calculator.
How to choose
- Start with your date. When do you need the money? A school fee due in four months points to the 91-day bill, not the 364-day one.
- Think about where rates are heading. If rates look set to fall, a longer bill locks in today's rate. If they look set to rise, shorter bills let you reinvest higher. Nobody knows for sure; the CBK's Central Bank Rate decisions (now 8.75%) are one clue.
- Consider a ladder. Split your money so something matures every few months. For example, KSh 50,000 into a 364-day bill every three months: after the first year, one bill matures each quarter, each having earned the one-year rate. A quicker start is to split across all three lengths now, so the first money comes back within three months.
Ready to buy? Our DhowCSD guide walks you through it.
Frequently asked questions
Which T-bill pays the most in Kenya?
The 364-day T-bill usually pays the highest rate, but not every week. For bills issued 12 Oct 2026 it paid 9.04% before tax, against 8.87% for the 182-day bill and 8.76% for the 91-day bill.
Is a 91-day or 364-day T-bill better?
Neither is better for everyone. The 364-day bill usually pays more and locks in the rate for a year. The 91-day bill returns your money sooner and lets you reinvest at new rates, higher or lower.
How does the 182-day T-bill compare with the 91- and 364-day bills?
The 182-day bill sits in the middle: it usually pays a little more than the 91-day bill and a little less than the 364-day bill, and returns your money in six months. For bills issued 12 Oct 2026 it paid 7.49% a year after tax; see this week's rates for every figure.
Can I sell a T-bill before it matures?
Only at a cost: T-bills aren't traded on the stock exchange, so the usual route is a rediscount with the Central Bank of Kenya at a penalty rate.
For education only, not financial advice. Rates change at every weekly auction: check the Central Bank of Kenya's results and DhowCSD before you invest.