$ACAD is one of biggest losers #stocks today. read more:

ACADIA Pharmaceuticals Inc. (symbol: ACAD) was one of the worst losers of
the trading day today (2016-01-06), losing -15.15%. The number of shares
that changed hands was 4,532,265, or about 4 times the average daily volume
in the stock.
The closing price was $29.24, amounting to a market cap of $2,950,000,000,
about -43.76% off the highest price in the last 12 months. The stock has
been trading at a range between $28.52 and $51.99.
ACAD is in the Major Pharmaceuticals industry, part of the Health Care
sector. It first went public in 1985.