The online services Betterment and WealthFront explicitly state they hold the efficient markets hypothesis is true and invest exclusively in broad-market index funds. I consider their approach to be an alternative to using Vanguard, which is to say, they offer an excellent service and many people would be well to use them, but I believe more optimal investing is possible. In my opinion it is not really possible to scale a market-inefficiency-exploiting strategy to the level that Betterment and WealthFront are after.