I believe many of the shares retired were those shares given to key employees as pay before revenues were realized. Once revenues started rolling in they were able to buy the shares back from the key employees and retire them. I am sure the employees are still holding some of those shares, but received payment for many of the shares. This would benefit both the employees and the company as the employees would not be selling the shares on the open market dropping the price and in fact the market cap would increase as less shares were OS making the shares the employees still owned worth more. That is why the restricted shares dropped each time shares were retired. The shares that have been retired were not bought back on the open market they were bought back through private negotiations. IMHO GL