IMHO, the etf's are going to trade a certain way due to algorithm influence and manipulation, and the stocks are influenced similarly but are going to be more susceptible to dramatic changes in their individual supply and demand. And while the two will meet in the middle due to arbs, baskets of some stocks can be manipulated to compensate for dramatic changes in others, so they are individually less likely to change the course of the index etfs. So as a result, the etf's are in general a bigger driver of volatility than the individual stocks (and that may be unpopular, but is imo.)