Investing & risk
Yield to Maturity Is a Cash-Flow Equation
Learn how yield to maturity links bond prices to scheduled payments, why reinvestment matters, and where the calculation differs from realized performance.
The learning desk
Evaluate an investment by exposure, cash flows and downside
What economic risk is owned, and when might cash be required?
The question to carry through
What economic risk is owned, and when might cash be required?
Begin with the claim being purchased rather than the most recent return. A share, a bond and a fund interest represent different cash-flow and ownership structures. The next task is to identify overlapping exposures and possible common shocks. A collection of familiar labels can be concentrated in the same issuer, industry or risk factor, even when it is held through multiple accounts.
Use returns as measurements with stated dates and conventions, not as promises. Separate a price move from distributions, and separate a portfolio’s time-weighted performance from an investor’s experience of deposits and withdrawals. The worked examples in this path are deliberately limited. They help explain which mechanism can produce a loss, not calculate a probability that an investment is suitable for you.
Identify the claim and its conditions
Read the ownership explanation and list what the holder receives, what can change and which payments are conditional. Do not equate residual ownership with a scheduled repayment promise. A valuation should be connected to the rights and cash flows being valued.
Read the analysisStock Ownership Is a Residual Claim, Not a Repayment PromiseMap economic concentration
Trace holdings through any overlapping funds and compare risk drivers. The goal is to identify exposure, not to count tickers. Test what would happen if one important issuer or shared factor declined while the rest of the simplified portfolio remained unchanged.
Read the analysisDiversification Depends on Relationships, Not Just HoldingsConnect withdrawals to the return path
Follow the same invented return sequence with withdrawals in different orders. Inspect the remaining balance before assuming an average return describes spending capacity. A dated cash obligation can force a sale at an unfavorable time.
Read the analysisWithdrawals Make the Order of Returns MatterOriginal hypothetical case
The same loss rate with different exposures
- Portfolio value USD 10,000; one exposure falls 20%.
- All other exposures remain unchanged; no fees, borrowing or distributions.
Result (USD scenario loss)
- 1. 20% exposed
- 400.00
- 2. 40% exposed
- 800.00
- 3. 60% exposed
- 1,200.00
Shared zero-based value scale. Range: 0.00 to 1,200.00, in the units above. Case numbers match the labels; no probability or time trend is implied.
Hypothetical model, not observed market data or a forecast. Assumptions above; original values and calculations below.
| Scenario | Result (USD scenario loss) |
|---|---|
| 20% exposed | 400.00 |
| 40% exposed | 800.00 |
| 60% exposed | 1,200.00 |
The scenario loss rises with the economic exposure. This is not a recommended allocation and does not assume the remaining assets actually stay unchanged in a market shock.
Inspect the arithmetic · Scenario loss with 60% exposure
((10000 * 0.59999999999999998) * 0.20000000000000001) = 1,200.00 USD scenario loss.
The arithmetic above checks the stated case. The chart uses the values in the accompanying table. Neither the case nor the comparison represents observed outcomes or a probability forecast.
Before applying the conclusion
Three checks worth recording.
- Which cash-flow or ownership claim is being bought?
- Could several holdings share the same downside driver?
- Would a dated withdrawal change the ability to hold through a loss?
Keep the definitions close.
From the library
Further reading
Investing & risk
A Backtest Can Be Accurate Arithmetic and Weak Evidence
Learn how hindsight, parameter selection, missing costs, and unavailable information can inflate a simulation without establishing a repeatable investment edge.
Investing & risk
Individual Bonds and Bond Funds Have Different Cash-Flow Structures
Compare a bond's maturity promise with a fund's continuing portfolio, and separate diversification benefits from assumptions about recovering an original investment.