I know you didn't address your comment to me, but let me hasten to say that an even better question is, "Why did the stock jump almost 2 dollars on the morning of Oct. 5, to $41.20, and then fall 6 points over the next 6 trading days?"
My hunch is that the stock was shorted at 41-40, possibly even at 39-38, by a few parties acting in concert with one another. Acting illegally, in point of fact.
The news on October 4 was enormously positive. We learned the FDA granted Nuplazid breakthrough therapy in dementia-related psychosis (a huge market), and we learned Acadia is running a pivotal phase 3 in the indication with excellent chances for success.
If this were a stock not manipulated by a couple of scumbags, it would've stayed in the low 40s or risen even higher.