Following a full in-kind legal account transfer, you may still see residual positions in the form of fractional shares in your account. Since the ACATS system only supports whole share transfers, the fractional share values will be liquidated shortly after a full transfer. Betterment will collect any accrued management fees from the fractional share liquidation, then send the remaining cash proceeds to the receiving firm via ACATS.
Following a partial transfer, accrued management fees will be collected on the remaining balance at the end of the month, or when you initiate a full withdrawal.
Betterment does not charge any fees to transfer out or close your account. There is also no minimum transfer amount nor a limit on the number of transfers you can complete.