Impairment test under US GAAP
Under US GAAP, the carrying amount of the assets is compared to the undiscounted future cash flow of the assets generated. If the amount of undiscounted cash flow is highr than carrying amount, no impairment loss is required. If the amount of undiscounted future cash flow is lower than the carrying amount. The fair value of the assets is required to measured which is based on market participants expectation. The impairment loss is the different between the carrying amount and the fair value of the assets.