How to compare investments on the same time horizon

Overview
Investment comparisons often go wrong before any formula is used. A short-tenor product is compared with a one-year product, one quote is annualised while another is a holding-period return, and different liquidity assumptions are ignored. The result looks precise but answers no useful question. The first rule of comparison is to put every alternative on the same goal date and define what happens to money between maturities.

How it works in practice
If a 90-day instrument matures before your one-year goal, you must make a reinvestment assumption for the remaining period. Assuming the same rate will repeat is a forecast, not a fact. A 364-day instrument may lock a known cash flow but provide less flexibility. Funds may offer variable return with easier access. A fair model shows the reinvestment assumption explicitly and includes fees each time money rolls over.

A practical process
1. Choose one target date for the decision.
2. Convert every product into actual cash flows up to that date.
3. For early maturities, state a conservative reinvestment assumption instead of silently repeating the current rate.
4. Include all fees and realistic liquidity constraints.
5. Run a downside scenario where reinvestment rates fall or you need cash earlier than planned.

Worked example
Illustrative example: a 91-day bill appears to annualise to a high number, but your goal is one year away. You would need to reinvest several times. If later auction rates fall, the actual one-year cash outcome may be lower than the simple annualised display. Conversely, locking a one-year instrument removes some reinvestment uncertainty but may reduce flexibility.

Risks and limitations
- Reinvestment assumptions can create false precision.
- Annualisation can exaggerate what a short observed return will actually compound into.
- Liquidity needs can make the mathematically highest-return option unsuitable.
- Fees paid at every rollover can accumulate.

Verification checklist
Before acting, verify the exact product or security, the legal issuer or manager, the current date, the pricing or return methodology, the payment route, fees and liquidity terms. SmartMoney examples are educational and use simplified assumptions unless a dated source is explicitly named. Never transfer money because a screenshot, forwarded PDF or social-media message looks official. Navigate independently to the regulator, issuer, bank, broker, fund manager or merchant and reconcile the details.

Decision framework before comparing alternatives
A useful comparison keeps the time horizon and cash-flow basis consistent. Put every alternative on the same target date, write down the actual amount that leaves your account, estimate only cash flows that the product documents support, and list fees separately. If one option matures early, any assumed reinvestment rate is a scenario rather than a promise. If one option can fluctuate in market value, include a downside exit case. If liquidity differs, record the realistic number of business days required to get spendable cash. This framework prevents a higher-looking percentage from winning simply because it was calculated on a different denominator, tenor or reporting period.

Who should pause and verify further
Pause when the legal issuer or product is unclear, the payment destination differs from the verified institution, the return source cannot be explained, documents are undated, withdrawal terms are vague, or a seller creates urgency that prevents independent checks. Also pause when the investment would consume money needed for a known near-term obligation. A legitimate product can still be inappropriate for a particular cash-flow need, and a genuine institution can still be impersonated by a fraudulent channel. Verification is therefore both a product check and a transaction-channel check.

Records worth keeping
Save the current offer document, factsheet or source page; record the source date; retain the exact quote, fee schedule, payment evidence, transaction advice or contract note, ownership/custody record and expected maturity or redemption date. For market instruments, save the executed price rather than only the pre-trade quote. For funds, keep subscription and redemption confirmations. Good records make it possible to compare expected and realised returns, spot missing payments and resolve disputes without relying on memory. Store sensitive KYC and account material securely rather than forwarding it casually through messaging apps.

Frequently asked questions
Q: Why not just compare annual percentage rates?
A: Because the products may have different cash-flow timing, reinvestment requirements and liquidity.

Q: Can I assume today’s rate will repeat?
A: No. Treat that as a scenario, not a certainty.

Q: Should I always lock the longest tenor?
A: No. Match tenor to goal and liquidity need.

Q: What does SmartMoney’s calculator do?
A: It provides illustrative cash-flow math; current product terms still require source verification.

Primary sources to verify
- Central Bank of Nigeria — Government Securities: https://www.cbn.gov.ng/rates/GovtSecurities.html
- Securities and Exchange Commission Nigeria: https://sec.gov.ng/

What changed?
This article was expanded for SmartMoney’s pre-index editorial review so it contains a complete decision framework, worked example, risk section, verification steps and primary-source links. Market-sensitive figures are deliberately not frozen into this guide; live or dated rates belong in SmartMoney’s source-labelled market cards. If an official rule, offer term or market structure changes, the article should be reviewed and the change recorded rather than silently rewritten.

Bottom line
Use this guide to ask better questions, not to outsource the decision. The correct transaction is the one whose current terms you can verify and whose risk, liquidity and cash-flow pattern fit the job your money needs to do. For regulated financial products, confirm current details with the appropriate official source and authorised provider before committing funds.