text: **Stock-Based Compensation and Other Stock-Based**
  **Payments**
  
  *Stock Option Plans*
  Cash-settled share appreciation rights (SARs) are attached to all stock 
  options granted under our employee stock option plan. This feature 
  allows the option holder to choose to receive a cash payment equal to 
  the intrinsic value of the option (the amount by which the market price 
  of the Class B Non-Voting share exceeds the exercise price of the option 
  on the exercise date) instead of exercising the option to acquire Class B 
  Non-Voting shares. We classify all outstanding stock options as liabilities 
  and carry them at their fair value, determined using option valuation 
  techniques that comply with IFRS 2, Share-based Payment. We re- 
  measure the fair value of the liability each period and amortize it to 
  operating costs using graded vesting, either over the four-year vesting 
  period or to the date an employee is eligible to retire (whichever is 
  shorter). 
  
  We rely on estimates and assumptions when determining the amount 
  of current and deferred tax, and take into account the impact of 
  uncertain tax positions and whether additional taxes and interest may 
  be due. 
  If new information becomes available and changes our 
  judgment on the adequacy of existing tax liabilities, these changes 
  would affect the income tax expense in the period that we make this 
  determination. 