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

Horizon Pharma plc (symbol: HZNP) was one of the worst losers of the
trading day today (2015-09-28), losing -20.961%. The number of shares that
changed hands was 12,033,244, or about 3 times the average daily volume in
the stock.
The closing price was $18.005, amounting to a market cap of $2,870,000,000,
about -54.406% off the highest price in the last 12 months. The stock has
been trading at a range between $10.15 and $39.49.
HZNP is in the Major Pharmaceuticals industry, part of the Health Care
sector. It first went public in 2011.