Payouts of your available account balance are made daily and contain payments processed two business days prior (this is how long it takes for your pending account balance to become available on this schedule). Canadian accounts have a 7 day payout period.
For example, payments received on a Tuesday are paid out by Thursday, and payments received on a Friday are paid out by Tuesday. ACH payments take up to 5 business days to receive acknowledgment of their success or failure. Because of this, ACH payments take up to 7 business days to be reflected in your available balance.