$ATRA is one of biggest winner #stocks today. read more:

Atara Biotherapeutics, Inc. (symbol: ATRA) was one of the biggest winners
of the trading day today (2016-12-13), gaining 6.49%. The number of shares
that changed hands was 358,065, or about 1.7 times the average daily volume
in the stock.
The closing price was $18.05, amounting to a market cap of $520,920,000,
about -46.39% off the highest price in the last 12 months. The stock has
been trading at a range between $12.45 and $33.67.
ATRA is in the Biotechnology: Biological Products (No Diagnostic
Substances) industry, part of the Health Care sector. It first went public
in 2014.