I find it very hard to believe that the public has been holding 1 billion shares of this, and waited until now to unload it. These are more likely, imo.
In no particular order:
The company is buying back shares, to have more supply after the r/s
An investor is taking a position
Shares from a recently converted note are being sold
The company is selling shares
My posts are my opinion. Try not to be influenced by anything you read on any message board website unless you can confirm it.