- 29 -  Expected volatility was determined based on the historical movements in the closing price of the Company’s stocks  for a length of time to the expected life of each option.  The Company has estimated the forfeiture rate to be 0.00%. The fair value of each option granted is estimated at the time of the grant using the Black-Scholes option pricing  model with weighted average assumptions for the grants for the years ended December 31, 2012 and 2011 as  follows:  As of December 31, 2011, among the 10,071,000 outstanding options, 10,051,000 options were exercisable with a  weighted average exercise price of $0.25 and a weighted average remaining contractual life of 2.50 years. During  the year ended December 31, 2011, 1,151,500 stock options expired unexercised.  As of December 31, 2012, among the 9,739,500 outstanding options, 9,277,000 options were exercisable with a  weighted average exercise price of $0.19 and a weighted average remaining contractual life of 2.41 years. During  the year ended December 31, 2012, 52,500 stock options forfeited and 2,514,000 stock options expired unexercised. 2012 2011 Risk-free interest rate 1.27% 2.77% Expected dividend yield 0.00% 0.00% Expected stock price volatility 95% 99% Expected option life in years 4.43 5 Grant date fair value 0.049 $ 0.137 $ Outstanding at December 31, 2010 8,802,500 $ 0.28 Granted 2,420,000 $ 0.18 Expired (1,151,500) $ 0.32 Outstanding at December 31, 2011 10,071,000 $ 0.25 Granted 2,235,000 $ 0.10 Forfeited (52,500) $ 0.10 Expired (2,514,000) $ 0.39 Outstanding at December 31, 2012 9,739,500 $ 0.18 Number of Options  Weighted Average Exercise Price  A summary of the Company’s outstanding stock options as at December 31, 2012 and 2011 are as follows:  (c) Stock options (Continued)  14. Share Capital (Continued)  COMMANDER RESOURCES LTD.  (An Exploration Stage Company)  Notes to Financial Statements  For the Years Ended December 31, 2012 and 2011  (Expressed in Canadian dollars) 