How do I add an external account? To sync an external account to Betterment, log in from a web browser and click "Sync new" from "Home." Related articles When I sync a non-Betterment account, does Betterment store my username and password? External portfolio analysis assumptions What is your affiliation with Goldman Sachs? How do I deposit or transfer funds into Betterment? What accounts can I open with Betterment?