The vesting is based on relative performance, not absolute performance. Also, it is based on two- (and soon, three-) year performance periods. In other words, for August 24, 2015, it would be based on the TSR (total shareholder returns: capital gains + dividends) from August 23, 2013. The stock has done very well. The stock was selling for $71 then. In other words, it would have vested anyway.