Karen Firestone: Tech dominates the S&P 500. It's time to ask whether it's the best benchmark for investors

For many decades, the key professional goal of many in the investment management industry has been to produce returns that exceed those of the S & P 500 . Recently, I've begun to question that mandate. As the S & P 500 has become increasingly concentrated in sector and weight, it is worth questioning whether it still serves as an appropriate benchmark. In sticking with the broad-market index, we could inadvertently be exposing our clients and shareholders to additional risk. Answering that question assumes understanding why we use the S...