An available balance account is the account funded by a commitment account.  An available balance account is the balance available for spend.

A commitment account is the account that funds the available balance account with a commitment or liability pending settlement.

Disbursements flow funds from available balance accounts to external payment sources. Disbursement events are used to payout available balances.

Egress accounts are ledger accounts that maintain a balance of disbursements to external payment sources.

Funding flows funds from external payment sources to commitment accounts. Funding events are used to pay down liabilities in commitment accounts created by Contribution events. A debit in a commitment account results in a credit on an available balance account. This accounting technique allows the system to credit an available balance account with a liability that has not yet cleared or settled. Eventually, based on the use case, the liabilities accrued in the commitment account will be funded via funding events that pay down the liability.

Ingress accounts are ledger accounts that maintain a balance of funding from external payment sources.

Payees are providers of goods and services to individuals and have a customer relationship with a bureau. Payees can accrue an available balance via reimbursements and be paid out via multiple payment channels. An example of a payee is a general practice doctor.

Is the transfer of funds to or from an external payment source.

Payment sources reference external types of stored value custodied by external financial institutions or vendors. Example types are ACH, check, wire, card, direct to debit, brokerage accounts, etc. Payment sources are owned by organization resources such as bureaus, clients, individuals, payees and custodians.