The Investment Scientist

The 60/40 portfolio consists of 60% equity and 40% bond and is the standard portfolio for MZ Capital Management. Because a majority of my clients use a variation of this portfolio, I want to demonstrate how this portfolio has performed in the past. 

For this study, I used the S&P 500 for the equity portion and 10-year US treasury bonds for the bond portion, using market data from 1928 to 2025. Note that this period includes both the Great Depression and the Great Recession.

The portfolio was rebalanced every year to maintain the 60/40 allocation. I then analyzed six return intervals: 1 year, 2 years, 5 years, 10 years, 20 years, and 30 years. For each return interval, I calculated the average, best and worst annualized returns.  

Here are my results: