pcimino gave a great synopsis. The only thing I would add is that it all comes down to "news". If there's great news coming, the stock will rise no matter what exchange it's on.

The one thing that bothers me - is that if there is "great" news in the pipleline, PLRS should be able to get to the NAZ on their own. However, they may be thinking that they'll get more bang for their buck with rolling out big news on the NAZ via an RS.

As I and others have pointed out, without any positive news, the SP will drop like a rock. It will be a shorters favorite on the NAZ if they do not roll out any substantial news.