PS, the reason I looked into this and posted the screen.

Right now the giants have been the place to be, for a long time. The concentration is getting worrisome for those who believe in any degree of normalcy returning, but the market can remain (what some would call) irrational for longer than you can stand it. If they remain the only place to "keep up" and do well, then switching away from them too early is the same as being wrong--you risk a long stretch of underperforming, which is both maddening and not great for the pocketbook.

So the idea here is to have your cake and eat it too...if this screen worked as advertised, you could switch to that and still do well even if the giants continue to soar for years more...it removes the need of calling the relative top for one group versus another, since it does well anyway. Relative to cap weight index, specifically.

Sometimes subset A is best, sometimes subset B is best, so most folks want to be in the right one. But if subset C is pretty good all the time, there is no need to gamble on timing your switches.

Emphasis on "if", of course.

Jim