The Company evaluated its cost method investees for impairment by using valuation models based on  discounted future cash flows because there are no quoted fair value for such investments. Cost method  investees held with a carrying amount of NT$44 million were written down to their fair value of NT$24  million, resulting in an impairment charge of NT$20 million, which was included in earnings for year  ended December 31, 2009, and cost method investees held with a carrying amount of NT$99 million were  written down to their fair value of NT$40 million, resulting in an impairment charge of NT$59 million,  which was included in earnings for year ended December 31, 2010.  Certain non-financial assets and non-financial liabilities measured at fair value on a recurring basis  include reporting units measured at fair value in the first step of a goodwill impairment test, other non- financial long-lived assets and idle assets measured at fair value for impairment assessment. The Company  calculates these fair values using the market approach which includes recent market condition and other  economic factors as their fair value inputs. Other assets held with a carrying amount of NT$5 million  were written down to their fair value of nil, resulting in an impairment charge of NT$5 million, which was  included in earnings for year ended December 31, 2009, and other assets held with a carrying amount of  NT$94 million were written down to their fair value of NT$28 million, resulting in an impairment charge  of NT$66 million, which was included in earnings for year ended December 31, 2010.  Advertising and promotional expenses are charged to income as incurred. These expenses were NT$3,689  million, NT$3,413 million and NT$3,227 million for the years ended December 31, 2008, 2009 and 2010,  respectively.  Effective from January 1, 2007, the Company adopted the guidance of income taxes uncertainties.  The guidance prescribes a recognition threshold and measurement attribute for the financial statement  recognition and measurement of a tax position taken or expected to be taken in a tax return. The guidance  also provides guidance on derecognition, classification, interest and penalties, disclosure and transition.  The evaluation of a tax position in accordance with the guidance is a two step process. The first step is  recognition, where we evaluate whether an individual tax position has a likelihood of greater than 50%  of being sustained upon examination based on the technical merits of the position, including resolution  of any related appeals or litigation processes. For tax positions that are currently estimated to have a less  than 50% likelihood of being sustained, zero tax benefit is recorded. For tax positions that have met the  recognition threshold in the first step, we perform the second step of measuring the benefit to be recorded.  The actual benefits ultimately realized may differ from the Company’s estimates. The adoption of the  guidance did not have a material impact on the Company.  The Company did not identify significant unrecognized tax benefits for the year ended December 31,  2008, 2009 and 2010. The Company did not incur any interest or penalties related to potential underpaid  income tax expenses.  e. Advertising and promotion expenses  f. Income tax  F-79