Max works as a hub-and-spoke system, with a checking account as the center or 'hub' account, which in turn links to your higher-yielding online savings accounts as the 'spokes.’
The hub account in the center must be a checking account (and not a savings account), so as to comply with Regulation D, which limits you to no more than 6 outbound transfers from a savings account per month. Max's proposed monthly optimization uses no more than 1 outbound transfer per month from each savings account.
Please have a look at the following Knowledge Base article for all of the Max-supported checking accounts: Which checking accounts does Max support?
If you wish to link Max to one or more of your existing savings accounts, you can open a Max Checking account in as little as 60 seconds during sign up. Max Checking will serve as your ‘hub’ account, to which you can link any combination of checking, savings, and brokerage accounts at thousands of financial institutions nationwide.