I've thought about this a bit, and I think this is out of concern of someone possibly attempting a takeover.
Each party involved with the warrants is limited to holding a maximum 10% of outstanding shares, so they have to sell off anything in excess of that limit as they exercise them. However, even at that, they hold a pretty substantial combined balance of shares. If they were to work with another party interested in a takeover bid that also accumulated a sizable share count, they could hold a fair bit of power.
Correct me if I'm wrong, but the replacement value of the 4 plants is somewhere in the $400 - $500M price range, right?
and now brought the Madera plant back online. I think that's a pretty strong backwards looking, combined demonstration of the yearly earning power of PEIX.
So, what's the ability to generate $50-$100M in net income a year worth? Combine that with the current market cap, and I think that regardless of exactly how your numbers come out, you have to agree that the current market cap makes PEIX a very attractive takeover target.