Notes to Consolidated Financial Statements [in thousands of Canadian dollars, except per share amounts] December 31, 2012 and 2011 Critical accounting estimates and judgements (i) Impairment of intangible assets  (ii) Deferred tax assets (iii) Provisions for other liabilities (iv) Share-based payments In the process of applying CI’s accounting policies, management has made signifi cant judgements involving estimates and  assumptions which are summarized as follows: Indefinite life intangible assets, including goodwill, are tested for impairment annually or more frequently if changes in  circumstances indicate that the carrying amount may be impaired. The values associated with intangibles involve estimates  and assumptions, including those with respect to future cash infl ows and outfl ows, discount rates and asset lives. These  estimates require significant judgement regarding market growth rates, fund flow assumptions, expected margins and  costs which could affect CI’s future results if the current estimates of future performance and fair values change. These  determinations also affect the amount of amortization expense on fund contracts with finite lives recognized in future  periods. Deferred tax assets are recognized for unused tax losses to the extent that it is probable that taxable profits will be  available against which the losses can be utilized. Significant management judgement is required to determine the amount  of deferred tax assets that can be recognized, based upon the likely timing and level of future taxable profi ts together  with future tax planning strategies.  Due to the nature of provisions, a considerable part of their determination is based on estimates and judgements,  including assumptions concerning the future. The actual outcome of these uncertain factors may be materially different  from the estimates, causing differences with the estimated provisions. Further details are provided in Note 6.  The cost of employee services received (compensation expense) in exchange for awards of equity instruments recognized  is estimated using a Black-Scholes option valuation model which requires the use of assumptions. Further details regarding  the assumptions used in the option pricing model are provided in Note 7 [b]. 59