Key takeaways
- The discount-rate quote understates return. Convert to bond-equivalent yield before comparing.
- A ladder removes the need to forecast rates by accepting the average of both ends.
- Rung length should be set by when the money is needed, never by the yield on offer.
- Treasury interest is generally exempt from state and local tax, which changes comparisons.
- Ladders suit known future needs, not long-horizon growth or immediate emergency access.
T-bill quotes use different denominators
A bank-discount yield commonly uses face value and a 360-day year. An investment yield uses purchase price and a 365-day year. The same bill therefore displays different percentages under different conventions.
A ladder spreads maturity risk
Dividing funds across maturity dates creates recurring liquidity and reduces the need to reinvest the entire balance on one date. It does not guarantee a higher return. Its purpose is timing diversification and cash-flow control.
Match rungs to known needs
Set maturity dates around tuition, taxes, purchases or reserve tiers. Money needed soon should not depend on selling a longer security at an uncertain market price.
Compare after tax, fees and protections
CD insurance limits, early-withdrawal penalties, Treasury tax treatment, brokerage spreads and municipal credit risk can affect the usable return. Compare instruments with the same maturity and after-tax basis.
Bills are sold at a discount and quoted unusually
A Treasury bill pays no coupon. It is bought below face value and matures at face. The traditional discount-rate quote divides the discount by the face value and uses a 360-day year, which understates the actual return because the investment is the price paid, not the face amount. The bond-equivalent yield corrects for both and is the figure to use when comparing a bill to any coupon instrument or deposit.
Three yields, three different numbers
The discount rate, the bond-equivalent yield and the effective annual yield are all correct answers to different questions about the same bill. They differ because of the base used and the day-count convention. Comparing a bill quoted on a discount basis against a certificate of deposit quoted as an annual percentage yield without converting first will systematically favour the wrong instrument.
A ladder converts a timing decision into a schedule
Splitting capital across several maturities means a portion matures regularly and can be reinvested at prevailing rates. This removes the need to forecast: if rates rise, each maturity reinvests higher. If they fall, the longer rungs are still locked in. The cost is that the average yield sits between the short and long ends instead of at whichever end turns out to have been right.
Choosing rung spacing and total length
More rungs mean more frequent reinvestment and smoother rate exposure, at the cost of more administration and smaller individual positions. The ladder's length should be set by when the money is genuinely needed, not by yield: extending the ladder to capture a higher rate reintroduces exactly the liquidity risk the ladder was built to manage.
Reinvestment risk versus price risk is the trade
Short maturities have little price risk and high reinvestment risk: you get your money back soon and may have to accept a lower rate. Long maturities have the opposite. A ladder deliberately holds both, which is why it rarely produces the best outcome and rarely produces the worst. That predictability is the product.
Tax treatment differs by instrument and jurisdiction
Interest on Treasury securities is generally exempt from state and local income tax while remaining subject to federal tax, whereas bank deposit interest is typically fully taxable. This makes headline-rate comparisons misleading for investors in higher-tax jurisdictions, and it means the correct comparison is after tax at your own rates , not on the quoted yields.
Certificates of deposit are a different risk and liquidity profile
Deposits carry insurance up to statutory limits and typically an early-withdrawal penalty instead of market pricing. Treasuries carry sovereign credit and are sold at market price, which can be above or below what was paid. Neither is universally better: the deposit has a known exit cost and the Treasury has a known market.
When a ladder is the wrong tool
A ladder suits money with a known future need and a low tolerance for price variability. The result is a poor fit for a long-horizon growth allocation, where its predictability comes at a substantial expected-return cost, and for a genuine emergency reserve that may be needed before the next rung matures. Match the structure to when the money is actually required.
Worked with real numbers
What this looks like in the treasury bill calculator
The guidance above is easier to judge against figures. Using the treasury bill calculator worked example, moving purchase price from $7,800 to $11,700 changes the investment yield from -29.1% to 56.6%.
| Purchase price | Investment yield | Discount yield |
|---|---|---|
| $7,800 | 56.6% | 43.5% |
| $8,775 | 28.0% | 24.2% |
| $9,750 | 5.1% | 4.9% |
| $10,725 | -13.6% | -14.3% |
| $11,700 | -29.1% | -33.6% |
Open the Treasury Bill Calculator to use your own numbers →
The inputs behind those figures
| Input | Value | Definition |
|---|---|---|
| Maturity value | $10,000 | Enter the maturity value for this scenario. |
| Purchase price | $9,750 | Enter the purchase price for this scenario. |
| Days to maturity | 182.0 days | Enter the days to maturity for this scenario. |
What goes wrong
Common mistakes
Each of these produces an answer that looks reasonable, which is why they survive review. To catch them in t-bills, cds and maturity ladders, rerun the treasury bill calculator with a different assumption and check whether the result moves in the direction the guidance predicts, since an error that survives that test is usually in one of the inputs and not in the arithmetic.
| The mistake | Why it misleads | Do this instead |
|---|---|---|
| Comparing a bill's discount rate to a deposit's annual percentage yield | They use different bases and day counts. So the comparison is not like for like. | Convert the bill to bond-equivalent or effective annual yield first. |
| Extending the ladder to capture a higher long rate | It reintroduces the liquidity risk the ladder existed to manage. | Set the maximum maturity from when the money is needed and accept the resulting yield. |
| Comparing yields before tax | Treasury interest is generally state-tax exempt while deposit interest usually is not. | Compare after-tax yields at your own marginal rates. |
| Using a ladder as an emergency fund | Money is only available when a rung matures, and selling early exposes you to market price. | Keep the reserve in genuinely liquid form and ladder only what has a known future date. |
People also ask
Frequently asked questions
How many ladder rungs should I use?
Use enough to match meaningful liquidity dates without creating unnecessary administration.
Does a ladder eliminate reinvestment risk?
No. It spreads reinvestment across dates instead of concentrating it.
How is a T-bill's yield different from its discount rate?
The discount rate divides the discount by the face value using a 360-day year. The bond-equivalent yield divides by the price actually paid using a 365-day year. Because the price is lower than the face and the year is longer, the bond-equivalent yield is always higher, and it is the one that is comparable to other instruments.
How many rungs should a ladder have?
Enough that a maturity arrives as often as you want the option to reinvest or spend, and few enough that each position is worth the administration. The total length matters more than the count: it should match when the money is genuinely needed.
What happens to my ladder if rates fall?
Maturing rungs reinvest at the new lower rates while the longer rungs keep their original higher ones. So the average yield declines gradually , not immediately. That gradual adjustment in both directions is the main benefit of the structure.
Are Treasuries safer than CDs?
They carry different risks instead of strictly less. Treasuries carry sovereign credit risk and market price risk if sold early. Insured deposits carry institution risk covered up to statutory limits, with an early-withdrawal penalty instead of market pricing. Which is preferable depends on amount, horizon and tax situation.
Can I sell a bill before maturity?
Yes, on the secondary market at the prevailing price, which may be more or less than you paid depending on how rates have moved. For very short bills the price variation is small, which is part of why they are treated as near-cash.
Which input moves the investment yield most in the treasury bill calculator?
Ranked by how far each moves the investment yield across the range tested: maturity value (41.1%, 800%), purchase price (41.6%, 808%) and days to maturity (1.0%, 20%).
How much does maturity value matter in the treasury bill calculator?
The worked example uses $10,000. With the other inputs left at the worked example, moving maturity value from $9,000 to $11,000 takes the investment yield from -15.4% to 25.7%, a swing of 800% of the worked-example figure.