If you need to close your account, the process is simple. Log in below and click your name in the header. From there you will select "Settings" which is where you will click on "Accounts" from the sub-header. Once to this page, you will click the three dots towards the right of the account you are looking to close. You then will be asked to answer one of your security questions:
Please contact us at email@example.com if your decision to cancel is based on any problems you may be experiencing. If you simply need access to your funds, note that there are no fees for accounts with a $0 balance, so feel free to withdraw and keep your account open until you are ready to invest with us again.
If you would like to try Betterment again in the future, simply click "Add Account" at the right hand side of your Summary page.