The Importance of Monthly Returns in Stock Market Investing
When planning an investment strategy, most investors focus on annual returns. However, examining the range of monthly returns in stock market investing provides valuable insight into volatility, risk management and the effects of compounding.
Stock indexes tend to experience periods of positive and negative monthly returns that average out to long-term gains. Understanding the distribution of these monthly fluctuations can help temper unrealistic expectations and equip investors to manage inevitable downturns.
This article explores why examining monthly returns matters, including analyzing:
• The historical spread of monthly returns
• Impacts of volatility on performance
• Importance of dollar-cost averaging
• Effects of compounding over time
With this background, investors can develop more realistic expectations based on how the stock market has behaved in the past. This perspective can improve long-term returns through behavior adjustments and strategic allocations.
The Spread of Historical Monthly Returns
Examining monthly returns data for major U.S. stock indexes like the S&P 500 dating back decades reveals:
• Returns vary widely: Monthly gains and losses typically range from around -10% to +10%, though extremes outside this band have occurred. Greater volatility characterizes shorter time periods.
• Negative months are common: On average, stock markets have 2-3 negative months per year. However, drawdowns can cluster, with losses persisting for multiple months.
• Positive months outnumber negatives: About 2/3 of months over time have resulted in gains. Greater frequency of positive months helps produce the historical average annual return around 10%.
• Month-to-month changes fluctuate: Index returns from one month to the next rarely follow a predictable pattern. Large shifts in either direction are common.
• Returns cluster around average: When viewed as a distribution, monthly returns cluster most densely around the long-term average monthly gain of 0.8%. But outliers occur more frequently than a standard distribution would predict.
This historical spread of monthly returns illustrates the inherent unpredictability and volatility of short-term stock market investing. Understanding this variability helps set proper expectations and develop strategies to manage inevitable downturns.
How Volatility Impacts Performance
Short-term volatility in monthly returns can significantly impact investor performance due to:
• Underperformance during drawdowns: Losses that cluster for multiple months can cause investors to underperform had they invested a lump sum at the start of the period. Returns depend on timing of cash infusions.
•Effects of compounding: Large monthly losses compound by reducing the principal on which future gains can accrue. Although markets ultimately recover, the effects of compounding lower asset values persist.
•Behavioral reactions: Many investors pull funds or pause contributions during volatile periods, exactly when assets are cheaper. This behavior exacerbates underperformance relative to a buy-and-hold strategy.
•Reinvestment risk: Investors face reinvestment risk by needing to invest proceeds and income from existing assets at unpredictable future rates. Short-term volatility increases this risk.
Examining the historical spread and effects of monthly return volatility thus reveals risks drawdowns pose to investor performance and goals. Understanding these impacts can inform strategies to mitigate volatility’s influence.
