We continue to receive questions about the degree to which the top 10, 25 and 50 companies in the S&P 500 Index, by market capitalization (cap), are influencing the performance of the index in the current bull market.

The price-only returns featured in the table are shaded in either gray or blue. The gray shaded years indicate that a broad number of stocks in the S&P 500 Index were participating in the bull market, while the blue shaded years indicate that the top 10, 25 and 50 stocks garnered more favor from investors. 

After three consecutive years (2015-2017) in which the top 10, 25 and 50 companies with the largest market caps significantly outperformed the broader S&P 500 Index, the index has outperformed the top 10 and 25 constituents year-to-date through June 2018.   

We included 1998 and 1999 to remind investors of what top-heavy performance can look like at the extreme. If you recall, the climate in the equity bull market back in the latter half of the 1990s was characterized by former Federal Reserve Chairman Alan Greenspan as "irrational exuberance."

The bull market, as measured by the S&P 500 Index, commenced in March 2009. From 3/9/09-12/31/09 (not shown in table), the S&P 500 Index posted a total return of 67.80%, compared to 97.20% for the S&P 500 Equal Weighted Index, according to Bloomberg. 

From 3/9/09-6/29/18 (current bull market), the S&P 500 Index posted a cumulative total return of 388.64% (18.57% on an average annualized basis), compared to 498.33% (21.18% on an average annualized basis) for the S&P 500 Equal Weighted Index, according to Bloomberg. 

Those returns suggest that this bull market has been inclusive, rather than one dominated by the biggest companies, in our opinion.