The latest I can find is the 2012 Annual Report buda.
At that time Retzos had 12 million BLTOB. This is exactly how many were placed up for sale as a single parcel last week. Some have already been bought, leaving the current number.
If they had more heads than shown in that report (15,706,419) then they've probably been exiting for a while.
One theory is that they have sold these heads into recent strength and are now selling the remaining oppies.
BLT Price at posting:
37.5¢ Sentiment: LT Buy Disclosure: Held