If you received a check without a rollover tracking number (listed on your Transfer instructions), please write the number anywhere on the front of the check with a pen, then mail the check to the address listed below. These instructions only apply if you’d like to roll your funds into a Betterment IRA. If you’d like to transfer funds into an existing Betterment 401(k) plan through your employer, follow these instructions instead. Regular mail: Betterment P.O Box 203945 Dallas, TX 75320 ...