Introduction
Stocks and Treasury bills represent two distinct ends of the investment spectrum. Stocks, often exemplified by broad market indexes such as the S&P 500, offer ownership claims on companies and entitle investors to potential dividends and capital appreciation. Three-month Treasury bills, issued by the U.S. Department of the Treasury, serve as the quintessential “risk-free” instrument, backed by the full faith and credit of the federal government. This article examines and compares the objective performance metrics of these two asset classes, highlighting their historical return profiles, risk characteristics, real (inflation-adjusted) outcomes, and considerations for different investment horizons.
Historical Return Comparison
Over long spans of time, equities have delivered substantially higher nominal returns than Treasury bills. On a multi-decade basis extending back to the late 1920s, the capitalization-weighted S&P 500 has generated average annual nominal returns in the range of approximately 9 percent to 10 percent. In contrast, three-month Treasury bills have yielded average annual nominal returns of roughly 3 percent to 4 percent.
When focusing on more recent periods, such as the ten-year span leading up to mid-2025, the difference becomes even more pronounced. During that interval, the S&P 500’s average annual nominal total return—including reinvested dividends—was approximately 11 percent, whereas three-month Treasury bills averaged close to 2 percent per year. These figures illustrate that the magnitude of outperformance by stocks can vary by market cycle, yet the general pattern of higher equity returns persists across both long-term and recent-term evaluations.
Real Returns: Adjusting for Inflation
Nominal returns do not account for the erosion of purchasing power caused by inflation. After adjusting for inflation, stocks have delivered average annual real returns of around 6 percent over extended time frames. By comparison, the real yield on three-month Treasury bills has hovered near zero on average, often registering in the range of 0 percent to 1 percent.
The persistence of a positive equity risk premium in real terms underscores stocks’ ability to reward investors not only for bearing the additional volatility and risk of corporate performance but also for preserving and growing purchasing power over inflationary periods. In contrast, Treasury bills, while preserving nominal capital, typically fail to outpace inflation by a meaningful margin, resulting in limited or negligible real wealth accumulation.
Volatility and Risk Considerations
Stocks exhibit significantly higher volatility than Treasury bills. Measured by the standard deviation of annual returns, broad equity indexes such as the S&P 500 have experienced swings that frequently exceed 15 percent to 20 percent. Price declines of 30 percent or more in individual years have occurred multiple times across market history.
Treasury bills, with maturities of three months, display minimal price fluctuation and near-constant yields between issuance and maturity. Investors in Treasury bills face negligible market risk but are exposed to reinvestment risk—the uncertainty of rolling into new bills at potentially lower yields. Furthermore, during certain periods of rising inflation, real returns on Treasury bills can turn negative, eroding purchasing power even while nominal capital remains intact.
The Equity Risk Premium
The difference between average equity returns and risk-free rates is known as the equity risk premium. Historically, this premium has averaged in the range of 6 percent annualized on a nominal basis. This premium compensates investors for bearing the business-cycle, market-sentiment, and corporate-governance risks inherent in equity ownership.
Over shorter spans—such as the 10-year window referenced earlier—the annualized equity risk premium can fluctuate. At times it has exceeded 8 percent, while in other periods it has compressed toward 6 percent or lower, depending on prevailing market valuations and Treasury bill yields. Even in environments of elevated short-term interest rates, stocks have tended to maintain a positive premium, reflecting their potential for earnings growth and dividend accrual.
Short-Term Scenarios: When Bills Can Outshine Stocks
Although stocks outperform Treasury bills on average over long horizons, there are episodic short-term exceptions. During major market downturns, such as the global financial crisis or other economic shocks, short-term interest rates can exceed negative or sharply falling equity returns. For example, in mid-2008 when equities plummeted, three-month Treasury bills continued to offer positive yields in the high single digits, resulting in Treasury bills outperforming stocks over that specific period.
Similarly, in periods of rapid monetary tightening, newly issued Treasury bills can carry elevated yields that temporarily surpass the trailing performance of the stock market. Investors focused on capital preservation over very short horizons may find Treasury bills preferable during such episodes, although the opportunity cost of forgoing potential equity gains in subsequent recoveries should be considered.
Time Horizon and Compounding Effects
A key factor in the stocks-vs-bills debate is investment horizon. The compounding effect of higher equity returns becomes more pronounced over longer periods. For instance, a hypothetical $1,000 investment earning an average of 10 percent annually in stocks would grow to more than $17,000 after 30 years, whereas the same sum invested in Treasury bills at an average of 3 percent annually would reach around $2,400.
Shorter horizons narrow the wealth gap, and there may be spans of two years or three years during which Treasury bills outperform equities. However, extended time frames generally favor equities due to the power of reinvested returns and recovery from drawdowns. This compounding differential underscores why many retirement-oriented strategies emphasize a significant equity allocation for participants with longer accumulation phases.
Suitability and Investor Objectives
The choice between stocks and Treasury bills should align with an investor’s objectives, time horizon, and risk tolerance. Treasury bills serve well for capital preservation, emergency funds, and short-term liquidity needs. Their stability and predictable nominal return profile make them a core component of cash management strategies.
Stocks, by contrast, are suited for investors seeking long-term growth and willing to accept periods of volatility. For individuals with long investment horizons—such as those saving for retirement decades away—equities offer the potential to outpace inflation and build substantial real wealth. Portfolio construction often involves blending both assets to balance growth potential with risk mitigation, with the specific mix tailored to an investor’s stage of life and financial goals.
Inflation Protection and Income Considerations
Equities generally provide a degree of natural inflation protection through earnings growth and dividend increases that can keep pace with rising prices. Companies often adjust pricing, expand into new markets, and improve operational efficiencies, which can support nominal revenue and profit growth. Over time, these dynamics help equity investors preserve purchasing power.
Treasury bills, on the other hand, are fixed-rate instruments and do not benefit from inflationary pressures. Their real return can become negative when inflation exceeds the nominal yield. Investors seeking both income stability and inflation protection may therefore look beyond Treasury bills to other fixed-income instruments (for instance, Treasury inflation-protected securities) or balance their portfolio with equities.
Conclusion
An objective examination of historical data demonstrates that stocks have outperformed Treasury bills by a considerable margin over extended periods. The premium for equities reflects compensation for higher volatility and corporate-specific risks, yielding average nominal returns of roughly 9 percent to 11 percent annually versus 2 percent to 4 percent for three-month Treasury bills. Inflation-adjusted returns further magnify this differential, with stocks offering meaningful real wealth accumulation and Treasury bills providing minimal real return.
While short-term episodes exist in which Treasury bills may outperform equities, the compounding power of higher stock returns over time typically leads to substantial wealth differentials. The choice between these assets should rest on clear investment objectives, tolerance for price fluctuations, and requisite liquidity needs, with many investors finding a balanced approach most appropriate for navigating varying market cycles.
