Staff accountants may also perform duties such as accounts payable and accounts receivable. The management of working capital involves managing inventories, accounts receivable and payable, and cash. Accounts receivable is shown in a balance sheet as an asset. Pools or portfolios of accounts receivable can be sold in capital markets through securitization. For example, "accounts receivable" is the controlling account for the accounts receivable subsidiary ledger. Collections and cashiering teams are part of the accounts receivable department. If sales decreases proportionally to accounts receivable, DSO will not increase. The ending balance on the trial balance sheet for accounts receivable is usually a debit. Income resulting from contributed accounts receivable will then be allocated to the contributing partner. This is very common with uncollected accounts receivable or appreciated real estate. In contrast, companies that do accounts receivable financing may charge per week or per month. Blackbaud's first product was Student Billing, an accounts receivable system geared toward private grade schools. A second key service is the operation of the accounts receivable function. This creates a receivable owed from the insured to the insurer. When a sale is made on account, revenue is recorded along with account receivable.