Strong Breadth Is Driving a Historic Week for This S&P 500 Alternative

It’s been a great week for members of the S&P 500, but not the index itself. The index, which weighs all stocks in the traditional S&P 500 as if they were the same size, is up 1.1% this week. The S&P 500, which gives more weight based on market cap, is down 2.4%.