Any quantitative strategy is susceptible to being reduced to an index, and along with this, to transparency and routine. Once this happens, that "alpha" becomes "beta," and the 2 + 20 fees are no longer available. A manager in search of alpha will have to move beyond that strategy, peeling away that layer of the onion and going to a deeper, not-yet-indexable, strategy.
Since transaction costs and the illiquidity of certain portions of an index make ideal tracking impossible, there will be a difference between the return of a tracking ETF, such as those tracking ETFs that are structured as UCITS in Europe, and the return of the underlying index or benchmark. The European Securities and Markets Authority maintains that investors should be informed of the factors that are likely to affect the size and the volatility of this difference.