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

Portola Pharmaceuticals, Inc. (symbol: PTLA) was one of the worst losers of
the trading day today (2016-03-25), losing -29.18%. The number of shares
that changed hands was 14,702,730, or about 15 times the average daily
volume in the stock.
The closing price was $20.27, amounting to a market cap of $1,090,000,000,
about -65.03% off the highest price in the last 12 months. The stock has
been trading at a range between $20.0 and $57.96.
PTLA is in the Major Pharmaceuticals industry, part of the Health Care
sector. It first went public in 2013.