... and thus the rise of “smart Beta” funds. The fact that many market indices are price-weighted is considered a flaw - consider, for example, that a stock with a 3x higher price in the DJIA will move the index 3x as much, regardless of market cap. Smart Beta funds attempt to adjust capital allocation by using different criteria to determine how much of each security to hold - for example, dividend yield rate, or volatility. Overall, this means that moves in and out of a particular security by a passive smart Beta fund become somewhat separated from the moves of its parent index.
More generally, the interesting thing about optimal portfolio funds is that they move counter to price. Appreciation in a particular asset class will cause that asset to be over-weighted in the portfolio, and the response will be to sell some of it, or buy more of everything else, to get back to the target ratios. Conversely, you find yourself buying into asset classes that keep falling (like natural resources over the past 5 years or so...), with the implicit assumption that some day they will rebound.