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

Merrimack Pharmaceuticals, Inc. (symbol: MACK) was one of the worst losers
of the trading day today (2016-07-14), losing -4.48%. The number of shares
that changed hands was 1,802,207, or about 1 times the average daily volume
in the stock.
The closing price was $5.12, amounting to a market cap of $653,950,000,
about -56.54% off the highest price in the last 12 months. The stock has
been trading at a range between $5.02 and $11.78.
MACK is in the Major Pharmaceuticals industry, part of the Health Care
sector. It first went public in 2012.