There are many reasons for the recent weakness in biotech stocks. As the year ends, some investors have definitely decided to lighten up on their winners. Catalyst Pharmaceuticals ( CPRX) was the best-performing stock between January and the end of September. And here's what Catalyst looked like in October: ^NBI data by YCharts
I probably had something to do with the Catalyst sell off. Acadia Pharmaceuticals ( ACAD) was the second-best performing stock January through September. And in October: ACAD data by YCharts
Celldex Therapeutics ( CLDX): Third-best return January through September. Not in October: nd CLDX data by YCharts
Picking up the pattern? Here's Biocryst Pharmaceutics ( BCRX), fourth best until Octoer: ^NBI data by YCharts
-- Reported by Adam Feuerstein in Boston. Follow Adam Feuerstein on Twitter.