NOTES TO THE CONSOLIDATED FINANCIAL  STATEMENTS  (RMB AND US$ AMOUNTS EXPRESSED IN THOUSANDS, EXCEPT PER SHARE DATA)  31.  Financial risk management objectives and policies (cont’d) Credit risk (cont’d) Liquidity risk China Yuchai International Limited | Annual Report 2013 119 As at December 31, 2012 One year or less Two to five years Total Rmb’000 Rmb’000 Rmb’000 Financial assets Trade and bills receivables 6,635,400 —  6,635,400 Other receivables, excluding tax recoverable 172,458 172,458 Cash and bank balances 3,397,565 —  3,397,565 Held for trading investment 48,761 —  48,761 10,254,184 —  10,254,184 Financial liabilities Interest-bearing loans and borrowings 2,459,169 116,687 2,575,856 Trade and other payables 6,176,328 —  6,176,328 Derivatives not designated as hedges – foreign exchange forward  contract 9,467 —  9,467 8,644,964 116,687 8,761,651 The table below summarizes the maturity profile of the Group’s financial assets and liabilities based on contractual  undiscounted payments. The Group monitors its liquidity risk and maintains a level of cash and cash equivalents deemed adequate by  management to finance the Group’s operations and to mitigate the effects of fluctuations in cash flows, and having  adequate amounts of committed credit facilities. Cash and fixed deposits are placed with banks and financial institutions which are regulated. At December 31, 2013, the Group had approximately top 20 customers (2012: top 20 customers) that owed the Group  more than Rmb 292.0 million (US$47.7 million) (2012: Rmb 246.4 million) and accounted for approximately 71% (2012:  56%) of accounts receivables (excluding bills receivables) owing respectively. These customers are located in the PRC.  There were 26 customers (2012: 35 customers) with balances greater than Rmb 1.0 million (US$0.2 million) accounting  for just over 95.4% (2012: 81.3%) of total accounts receivable (excluding bills receivables). The maximum exposure to  credit risk at the reporting date is the carrying value of each class of financial assets mentioned in Note 19. The Group  does not hold collateral as security. The allowance account in respect of trade and other receivables is used to record impairment losses unless the  Group is satisfied that no recovery of the amount owing is possible. At that point, the financial asset is considered  irrecoverable and the amount charged to the allowance account is written off against the carrying amount of the  impaired financial asset. The Group establishes an allowance for impairment that represents its estimate of incurred losses in respect of trade  and other receivables. The main components of this allowance are a specific loss component that relates to individually  significant exposures, and a collective loss component established for groups of similar assets in respect of losses  that have been incurred but not yet identified. The collective loss allowance is determined based on historical data of  payment statistic for similar financial assets.