The top 5 companies by market cap ( $FB, $AMZN, $AAPL, $MSFT, $GOOG )  already amount to 23.9% of the S&amp;P 500. At the same time, these 5 companies already make up  52.5% of the NASDAQ 100 implying that mega cap concentration in the NASDAQ 100 is higher than in the S&amp;P 500. 2/n https://t.co/Jr1RQY7edY