Direct answer: Stocks represent ownership in companies and earn returns from corporate earnings growth and dividends; bonds are loans to corporations or governments that earn fixed interest payments. Historically, U.S. stocks have returned approximately 10% per year (nominal) versus 5% for long-term U.S. government bonds, but with much higher volatility. Bonds serve as portfolio stabilizers: their lower volatility and historically negative or low correlation with stocks reduces portfolio drawdowns in equity bear markets. The stock/bond allocation is the most important single decision in portfolio construction.
Comparison Matrix: Stocks vs. Bonds
Key Takeaways
- Ibbotson's U.S. asset class returns (1926 to 2023): U.S. large-cap stocks approximately 10.3% per year; long-term government bonds approximately 5.7% per year; intermediate government bonds approximately 5.1% per year; U.S. Treasury bills approximately 3.3% per year. The equity premium (stocks over bonds) has averaged approximately 4.6% per year over this period.
- Volatility (standard deviation of annual returns): U.S. stocks approximately 19%; long-term government bonds approximately 10%; short-term bonds approximately 3%. The higher expected return of stocks comes with much higher short-term volatility.
- Correlation: U.S. stocks and long-term government bonds had negative correlation from 2000 to 2020 (bonds rose when stocks fell, providing portfolio insurance). In 2022, both fell simultaneously (positive correlation), because inflation-driven rate increases hurt both asset classes. The stock-bond correlation varies with economic regime.
- A 60/40 portfolio (60% stocks, 40% bonds) declined approximately 17% in 2022 versus the S&P 500 alone declining 18%; bonds provided only modest protection because the 2022 decline was rate-driven, not equity-specific. In 2020 (COVID crash), bonds provided stronger protection because the decline was equity-specific and the Fed cut rates.
- The traditional age-based allocation heuristic (100 minus age in stocks; 110 minus age in stocks) is a rough starting point, not a rigorous framework; the appropriate allocation depends on risk tolerance, time horizon, and whether the investor needs regular cash flow from the portfolio.
How Returns Are Generated
Stocks: total return comes from price appreciation plus dividends. Price appreciation reflects changes in earnings, earnings multiples (P/E ratio), and economic conditions. Dividends represent the cash return to shareholders from current earnings. Long-run stock returns are anchored by earnings growth plus dividend yield, modulated by changes in valuation multiples. Bonds: total return comes from interest income (coupon payments) plus price changes. Price changes are driven primarily by changes in interest rates (inverse relationship: rates up, bond prices down). The yield at purchase is the best predictor of a bond's total return over its full holding period. Bond returns over periods shorter than maturity also include the price volatility from rate changes.
Behavior in Economic Scenarios
Recession (falling rates, falling corporate earnings): government bonds typically perform well (falling rates raise bond prices); stocks typically fall as earnings decline; credit spreads widen, making corporate bonds underperform government bonds. Expansion (rising rates, rising corporate earnings): stocks typically outperform; bonds typically provide flat to slightly negative returns as rates gradually rise; credit spreads narrow, supporting corporate bond returns. Inflation (rates rising sharply, earnings mixed): both stocks and bonds can decline (as in 2022); TIPS and I-bonds provide inflation protection; commodities and real assets typically outperform; traditional government bonds perform worst. Deflation: government bonds dramatically outperform as rates fall to zero; stocks may continue to decline if deflation is accompanied by economic contraction (as in Japan in the 1990s).
Portfolio Role: Risk Reduction vs. Return Enhancement
The classic argument for holding bonds in a diversified portfolio is not that they will enhance returns (they are expected to earn less than stocks over long horizons) but that they reduce portfolio volatility, smooth drawdowns, and provide assets to rebalance into stocks during equity declines (buying stocks at lower prices with bond proceeds). For very long-horizon investors (30+ years, pure accumulation phase), a higher equity allocation (80% to 100%) maximizes expected terminal wealth. For investors approaching or in retirement who need to fund regular withdrawals, higher bond allocation reduces the sequence of returns risk that could impair the portfolio early in the distribution phase.
Duration and Credit Risk in Bond Allocation
Within the bond allocation, two main decisions: duration (short-term vs. long-term bonds) and credit quality (government vs. investment-grade vs. high-yield). Short-duration bonds provide stability with lower return and lower sensitivity to rate increases. Long-duration bonds provide higher yield with more interest rate risk. Investment-grade bonds have low default risk but trade at lower yields than high-yield. High-yield bonds have higher default risk and behave more like equities (correlated with stock market performance). A broad bond market index fund (Vanguard BND, iShares AGG) holds investment-grade U.S. bonds across a range of maturities; this is the standard core bond allocation for diversified portfolios.
Frequently Asked Questions
Are bonds safe investments?
Bonds have two distinct types of risk: credit risk (probability of default) and interest rate risk (price changes when rates change). High-quality government bonds (U.S. Treasuries, AAA-rated sovereigns) have near-zero credit risk but do carry interest rate risk: a long-term Treasury bond lost approximately 30% in 2022 when rates rose sharply. Short-term government bonds are closest to 'safe' in the sense of low volatility and low default risk; they give up return for stability. 'Safe' means something different for a 1-year T-bill versus a 30-year Treasury bond, even though both are backed by the same government guarantee.
How should inflation affect my stock/bond allocation?
In sustained high-inflation environments, nominal bonds perform poorly (fixed coupon payments lose real value). Inflation-protecting alternatives include: TIPS (Treasury Inflation-Protected Securities, with principal adjusting with CPI), I-bonds (savings bonds with CPI-linked interest), commodity funds, and real estate. Stocks provide some inflation protection over very long periods because corporate earnings tend to grow with the economy, but in high-inflation episodes (1970s, 2022), stocks also underperformed. A portfolio designed to be resilient across economic regimes typically includes a mix of nominal bonds, TIPS, equities, and real assets rather than relying on any single asset class.
Does the 60/40 portfolio still work?
The 60/40 portfolio's design rationale (stocks for growth, bonds for stability and negative correlation with equities) depended partly on the 2000 to 2020 negative stock-bond correlation. In 2022, that correlation turned positive, and 60/40 declined approximately 17%. The 60/40 is not 'broken': the 2022 decline was relatively modest compared to a 100% equity portfolio, and bonds still provided income and dampened volatility. But 60/40 investors should understand that in inflationary environments, the diversification benefit of bonds is reduced. Diversifying the bond allocation to include TIPS, short-duration bonds, or real assets alongside traditional nominal bonds can improve resilience across economic scenarios.