My recent stories in the Wall Street Journal - “What ETF Managers Do” and “ETF Managers Don’t Buy and Sell Securities. Usually.” - helped me put the role of the ETF manager (or index manager) in perspective. They are very driven by process and mandate as security selection, for the most part, has been removed from the position.

Instead, they must consider the margin of every move that they do have to make and how that will positively or negatively affect tracking difference.