What are the tax implications of the Betterment transfer?

Your account will be transferred to Betterment in-kind, which means that all of your investment positions (except mutual funds) will be moved "as is", without selling them and buying them again at Betterment.. 

There are two mutual funds that are in impact portfolios only. If you are invested in a core portfolio, your portfolio includes ETFs only, not mutual funds. To see what investments your portfolio includes, navigate to that goal from your dashboard or from the “Investing” drop-down menu in the navigation bar. Then scroll to the section labeled “What am I invested in?” (near the bottom of the page). You’ll see your portfolio’s target composition and a list of all the funds you own.

Following the transfer, your Ellevest portfolio strategy will be gradually transitioned to a substantially similar Betterment portfolio strategy (described in “Portfolio Comparison”), using additional cash flows (deposits, contributions, dividends) and automated rebalancing to help minimize tax impact. 

If you choose to opt out of the Betterment transfer and withdraw your funds, keep in mind this may cause capital gains or losses in your account.