The average stock in the S&P 500 gained just 0.20% in July. We ran our decile analysis on the index to see which stock characteristics drove performance during the month.
To run the analysis, we break the index into deciles (10 groups of 50 stocks each) based on the categories shown in the matrix below and then calculate the average July change of the stocks in each decile. The S&P 500 as a whole gained more than 1% in July, so the fact that the average stock in the index only gained 0.20% shows that the gains were concentrated in the megacap stocks.
The 50 largest stocks in the S&P gained an average of 1.46% in July, while the 50 smallest stocks in the index actually declined 1.80%. Typically when the market rallies, midcaps and smallcaps do well, but that certainly wasn’t the case in July.
Along with market cap, the three other categories that impacted stock performance the most in July were...