Be it restaurants, movies, sports teams or common stocks, to be popular is to be regarded with favor. The popularity of a common stock is reflected in the breadth of its ownership and its relative price movement. As the favor shown certain stocks is transmitted through meaningful changes in their prices, market indexes including such stocks are impacted. In turn, the dynamics of exchange-traded funds (“ETFs”) tracking such indexes can shift as well. These shifts then shape the return and risk behaviors of portfolios with particular ETF holdings. A review of the consequences of stock popularity can provide perspective for investing yet ahead.