Financial assets are assessed for impairment at each period-end date. In the case of an equity investment classified as available-for-sale, a significant or prolonged decline in fair value below cost is evidence that the asset is impaired. If an available-for-sale financial asset is impaired, the difference between original cost and fair value is transferred from equity to the income statement to the extent of any cumulative loss recorded in equity, with any excess charged directly to the income statement. Subsequent impairment reversals relating to previously impaired equity instruments are recorded in equity.