There are no minimum balance requirements to use Cash Reserve or Checking. This means that the minimum balance is $0. Your client can have as little or as much cash in Cash Reserve and Checking as they want—we won’t judge.
One thing to note is that the smallest deposit amount that can be made into Cash Reserve is $10. This is due to ACH transaction limitations.
Cash Reserve is provided by Betterment LLC, which is not a bank, and cash transfers to program banks are facilitated by Betterment Securities. Checking will be provided by Betterment Financial LLC, in partnership with nbkc bank.