Dr. Tim Edwards from S&P Dow Jones Indices explains that it is the smaller companies that have more potential for growth.
“Nowadays, you have potentially quite liquid, quite easy, quite low-cost ways to invest in mid and small caps. Not just in the US, but across the world. As we look at it right now, many investors, when they invest internationally, focus on the large-cap space and that may not be taking advantage of the full opportunity set they have”.
In short, large-cap index funds are a sensible investment over the long term.