To be honest, I have no idea how this director buying biz works either, but traditional "they love their own stock" reasons seem to no longer make sense across many observed small-cap purchases. So comments below are general and don't necessarily apply to PBP.
We have heard ad infinitum that director buying is a positive sign and get-in-while-you-can sort of thing on any number of little stocks. However, my experience has not suggested that to be true, and, more often than not, the stock eventually proves to be a basket case. On the surface, it looks like plenty of directors lose a lot of money this way... so, rightly or wrongly, I have come to see some of this director buying as a sort of "strategic corporate communications exercise". This is the only way much of what I have observed has made sense. I can only think either they want to convince investors that the company is in good heart, or they at least want to convince shareholders (and regulators) that they genuinely thought things were going to be okay (shortly before they all fell apart).
Where the funds come from and why they would sometimes appear to throw away so much is a puzzle. Paranoia makes me suspect complex transactions with small broking firms involving margin and stock lending premia could allow it to be done more cheaply than appears, but I don't know enough of the dark arts to be able to come up with a really coherent answer. All I have concluded over the past 6-7 years is that director buying is no longer a trustworthy signal.
PBP Price at posting:
49.5¢ Sentiment: None Disclosure: Not Held