With a time-weighted return, which is the industry standard return calculation used by Betterment, it is entirely possible to have a negative % return, despite having a net gain on your investments (or conversely, a positive % return with a net loss on your investments).
A time-weighted return assesses the performance of the underlying investments without being distorted by the timing or size of cash flows in and out of the account (i.e. deposits and withdrawals.)
Your time-weighted return is negative, because the underlying portfolio that you are invested in has decreased in value since you began investing. You can see that graphically by looking at the % Returns graph on your Performance tab in your account.
However, your dollar earnings are positive because you deposited the majority of your current investment when the value of your underlying portfolio was lower than it is now. You can see that by comparing the % Returns graph to the $ Values graph on your portfolio page.
Here's an extreme example to illustrate this:
Suppose, I invested $10 to start, and the market loses 50%. Now I have $5 in the account! Let's say I then make a $100,000 deposit and the market goes up 10% immediately after that. In this case, I would have positive dollar gains, since I just gained about $10k (much more than my initial $5 loss). It was not because the portfolio has performed well thus far – in fact, it’s been negative overall since I started (it went down 50% and then up 10%). However, most of my money was invested when I was at the bottom.
In short, my time-weighted return is negative because my portfolio performed badly. My simple dollar return is still positive, because of the timing of my cash flows. You can see both of these numbers in your own situation in the Summary tab of your Betterment account, by simply expanding each goal.
