Library
Personal Financial Planning — Part 5: Managing Investments · 7 of 10
Personal Financial Planning — Part 5: Managing Investments
finance CRITICAL

Risk, Return & Valuation

risk return compounding yield valuation interest-on-interest

Key Principle

Every investment decision rests on the risk-return trade-off: riskier investments must offer higher expected returns to attract rational investors, but higher risk never guarantees higher reward. Total return has three components — current income, capital gains, and interest-on-interest (reinvested income). The third component, often ignored, accounts for nearly 45% of a 20-year bond's total return.

Why This Matters

Investors who evaluate only yield or only price appreciation miss half the picture. An 8% bond held 20 years yields $4,700 with reinvestment but only $2,600 without — the $2,100 gap is pure compounding loss from failing to reinvest. (pp. 396-397) Meanwhile, investors who chase high returns without screening all seven risk types expose themselves to losses they didn't anticipate.

Good Examples

The reinvestment gap. $1,000 in an 8%, 20-year bond: coupon income = $1,600, principal recovery = $1,000, interest-on-interest = $2,100. Total with reinvestment = $4,700; without = $2,600. The reinvestment component is the largest single contributor. (p. 397)

The approximate yield formula. A unified estimator for stocks, bonds, and mutual funds: Approximate Yield = (Average annual income + (Ending value - Beginning value) / Holding period) / ((Beginning value + Ending value) / 2). Use this as a quick screen before deeper analysis. (p. 399)

Risk-return spectrum. From lowest to highest risk: T-bills < Treasury notes < long-term bonds < common stocks < real estate < options < commodities < precious metals. (p. 398)

Counterpoints

Risk does not guarantee reward. The risk-return relationship is an expectation, not a certainty. High-risk investments can and do lose money permanently. (p. 398)

Liquidity is not just "can I sell it." True liquidity requires both easy salability and a reasonable price. Forced sale at a steep discount is not liquidity. (p. 395)

Key Quotes

"The interest-on-interest component of a bond's return accounts for nearly 45% of the total return over a 20-year period." (p. 397)

"Few investors can time the market — and almost no one can do so consistently." (p. 407)

Rules of Thumb

  • Always reinvest periodic income to capture fully compounded returns (p. 396)
  • Evaluate total return (income + capital gains + reinvestment), never just yield (p. 396)
  • Screen all seven risk types: business, financial, market, purchasing power, interest rate, liquidity, event (p. 394)
  • Use the approximate yield formula as a first-pass screen for any investment (p. 399)
  • Set desired rate of return = risk-free rate + risk premium; reject investments that don't clear it (p. 401)
  • Weight reinvestment discipline more heavily the longer your time horizon (p. 398)

Related References