*Betterment's portfolio is designed to keep up with the market and not under-perform, but it is not designed to beat the market. Beating the market is difficult to do with any certainty and involves a lot of risk.
Betterment is a strong believer in passive investing. The majority of the evidence shows that active management, whether by individual investors or fund managers, cause more harm than good in net-of-fee returns. We therefore invest in low-cost, passive investments which always seek to match the market's performance. You will never out-perform or beat the market on a risk-adjusted basis in your Betterment portfolio, but you'll also never under-perform or pay for a manager who under-performs either.
You can therefore expect market-matching risk-adjusted returns in our portfolios.