A 3-month (91-day) treasury bill return depends on the auction rate and your amount — the discount you pay now is your yield. Here is how to compute what you will actually make.
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The Formula
You pay face value minus a discount computed from the annualised yield and the 91-day term. Roughly: return ≈ (annualised rate × amount × 91/365).
Example
At a 15% annualised rate, investing ₦1,000,000 for 91 days earns about ₦37,000 (15% × 1,000,000 × 91/365), paid as a discount up front.
What Changes the Number
- The auction's weighted average rate.
- Your bank's commission.
- Taxes on the interest.
- Whether you reinvest at maturity.
Reality Check
Confirm today's 91-day rate from the CBN auction or your bank before assuming returns — rates vary with policy.
FAQ
Do I get interest monthly on a 3-month bill?
No — the return is paid up front as the discount; face value returns at maturity.
What is the minimum to invest?
Often ₦100,000; confirm with your bank.
Related: T-Bill Cost and T-Bill Pricing.