Every contract is presented as a net position. If the company has performed more than the customer has been billed for, and payment depends on further performance, it is a contract asset. Once the right to payment is unconditional, only waiting for the due date, it becomes a receivable instead. If the customer has paid or been invoiced ahead of delivery, the excess is a contract liability, often called deferred revenue. Milestone billing on long projects is a common source of contract assets; annual software subscriptions billed upfront create contract liabilities. Companies disclose opening and closing balances and explain significant changes, so the balances need tracking per contract rather than as a single plug. Contract assets are also assessed for impairment like receivables. RightRev and Trullion track contract balances alongside revenue schedules.