Annual Report 2017

114 Annual Report 2017 2) Investments with fixed maturity that the management has the intent and ability to hold to maturity are classified as held-to-maturity and are included in non-current assets, except for maturities within 12 months from the statement of financial position date which are classified as current assets. 3) Investments intended to be held for an indefinite period of time, which may be sold in response to liquidity needs or changes in interest rates, are classified as available-for-sale; and are included in non-current assets unless management has expressed the intention of holding the investment for less than 12 months from the statement of financial position date or unless they will need to be sold to raise operating capital, in which case they are included in current assets. 4) Investments in non-marketable equity securities are classified as general investments. All categories of investments are initially recognised at cost, which is equal to the fair value of consideration paid plus transaction cost. Trading investments and available-for-sale investments are subsequently measured at fair value. The fair value of investments is based on quoted bid price at the close of business on the statement of financial position date by reference to the Stock Exchange of Thailand and the Thai Bond Dealing Centre. The unrealised gains and losses of trading investments are recognised in statement of comprehensive revenues and expenses. The unrealised gains and losses of available-for-sale in investments are recognised in other comprehensive revenues and expenses. Held-to-maturity investments are carried at amortised cost using the effective yield method less impairment loss. General investments are carried at cost less impairment loss. A test for impairment is carried out when there is a factor indicating that an investment might be impaired. If the carrying value of the investment is higher than its recoverable amount, impairment loss is charged to the statement of comprehensive revenues and expenses. On disposal of an investment, the difference between the net disposal proceeds and the carrying amount is charged or credited to the revenues and expenses. When disposing of part of the Company’s holding of a particular investment in debt or equity securities, the carrying amount of the disposed part is determined by the weighted average carrying amount of the total holding of the investment. 2.8 Accounts receivable and accrued income Accounts receivable and accrued income are carried at original invoice amount less allowance for doubtful accounts. The allowance for doubtful accounts is assessed primarily on analysis of payment histories and future expectations of customer payments, assessment of the future cash flows, known and identified instances of default and consideration of market trends. Bad debts are written off when incurred and recognised as part of other expenses in the statement of comprehensive revenues and expenses. 2.9 Property, plant and equipment Land is stated at cost less impairment losses. Property and equipment are stated at cost less accumulated depreciation and impairment losses. Depreciation is charged to the statement of comprehensive revenues and expenses on a straight-line basis over the estimated useful lives of each part of an item of property, plant and equipment, except for land which is considered to have an unlimited useful life. The estimated useful lives are as follows: Land improvements 5 years Buildings 10 - 50 years Building improvements 3 - 30 years Furniture and fixtures 5 - 20 years Office equipment 5 - 20 years Vehicles 5 - 7 years