Do buy-and-hold stock portfolios match index returns?
Core argument: Equal-weighted "do-nothing" portfolios returned an arithmetic mean of 14.02% over 1971–2025 versus 12.69% for value-weighted portfolios, with geometric means of 12.59% and 11.30% respectively, before trading costs.
I assess the impact during the 1971 to 2025 period of selecting portfolios based on equal-weighting versus value-weighting [i.e.weighting by market cap]. The data in Table 1 indicates that equal-weighted “do-nothing” portfolios outperform the value-weighted do-nothing portfolios overall. The arithmetic mean of 1-year-equal weighted portfolio returns is 14.02% while that of the value-weighted 1-year portfolio returns is 12.69%. The corresponding geometric mean returns are 12.59% for the equal-weighted portfolio compared to 11.30% for the value-weighted portfolio. “Do Nothing” portfolios, which continue to hold stocks even if they delist from the S&P 500 index, on average generate returns that match the index itself. On the other hand, equal weighted “Do Nothing” portfolios on-average outperformed value-weighted, at least before taking trading costs into account. Randomly selected narrow portfolios generate average returns similar to portfolios constructed from all constituent stocks, but underperform more than half of the time over longer holding periods. Strikingly, “Do Nothing” portfolios constructed from the largest S&P constituent firms have strongly underperformed portfolios constructed from all constituents over the past 55 years, especially when the investment is entirely in the largest stock. The outperformance of the largest stocks over the past dozen or so years is, in fact, atypical.



