I see this time after time on earnings and rev beats. It goes down.
In this case, earnings are lower than year 2011. Beating expectations is not all that great unless it is on a growth trajectory year over year.
I saw one company that grew 30% year on year with excellent outlook for another 30%, while it retired massive debt, and it dropped 25% and does not seem to have to have the life to get up off the mat.
There are only 4000 some stocks that trade on the US systems, all those traders have to have something to do, chances are this is mere manipulation. Heck for short term traders, temporary irritation for long termers.
Traders likely focused on the Q1 production guidance and what the possibility of lower oil & gas prices would mean for Q1 numbers in that context. Way overblown fears, though. And completely discounts the prior good news on reserves. Long term, Stone is much higher than these levels. But barring any significant bump in NG prices, I cant see the stock doing much until late 2Q into 3Q.