Why Biohaven Stock Dove by Nearly 20% on Thursday

Volatile biotech stock Biohaven (BHVN -19.41%) is prone to sharp movements both up and down. On Thursday, it had one of its down days, with its share price eroding by almost 20% on a development with a top regulator. That was on a day when stocks generally did well, as indicated by the S&P 500 (^GSPC 0.41%) landing in positive territory with a 0.4% rise. A regulatory extensionAfter market close on Wednesday, Biohaven divulged that the U.S. Food and Drug Administration's (FDA) Division of Neurology 1 is exte ...