(a) Basis of consolidationThe consolidated financial statements comprise the financial statements of the Company and its subsidiaries as at January 31, 2012. Subsidiaries are fully consolidated from the date of acquisition or creation, being the date on which the Company obtains control, and continue to be consolidated until the date that such control ceases. The financial statements of the subsidiaries are prepared for the same reporting period as the parent company, using consistent accounting policies. All intercompany balances, income and expenses, and unrealized gains and losses resulting from intercompany transactions are eliminated in full. For partly owned subsidiaries, the net assets and net earnings attributable to minority shareholders are presented as non-controlling interests on the consolidated balance sheet. Interest in Diavik Joint Venture HWDLP owns an undivided 40% ownership interest in the assets, liabilities and expenses of the Joint Venture. The Company records its interest in the assets, liabilities and expenses of the Joint Venture in its consolidated financial statements with a one-month lag. The accounting policies described below include those of the Joint Venture. (b) Revenue Sales from the sale of rough diamonds, fine jewelry and watches are recognized when significant risks and rewards of ownership are transferred to the customer, the amount of sales can be measured reliably and the receipt of future economic benefits are probable. Sales are measured at the fair value of the consideration received or receivable, net of value-added taxes, duties and other sales taxes, and after eliminating sales within the Company. (c) Cash resources Cash and cash equivalents consist of cash on hand, balances with banks and short-term money market instruments (with a maturity on acquisition of less than 90 days), and are carried at fair value. (d) Trade Accounts Receivable Trade accounts receivable are recorded at the invoiced amount and generally do not bear interest. The allowance for doubtful accounts is the Company's best estimate of the amount of probable credit losses in the existing accounts receivable. The Company reviews its allowance for doubtful accounts monthly. Account balances are written off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote.