…in recent years the top five stocks have accounted for a growing proportion of the Russell 1000. Indeed, the only time they accounted for even more was in early 2000—just before the internet and high-tech bubble burst—when indexing was riding a wave of popularity. Think of it this way: The top five companies account for 0.5% of the Russell 1000 by number and currently over 13% by weight. That’s concentration. We don’t know when the popularity of the top five will peak, but from historical experience we expect it will.