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

Enerplus Corporation Common Sto (symbol: ERF) was one of the worst losers
of the trading day today (2015-07-27), losing -10.31%. The number of shares
that changed hands was 1,983,901, or about 2 times the average daily volume
in the stock.
The closing price was $6.09, amounting to a market cap of $1,260,000,000,
about -74.37% off the highest price in the last 12 months. The stock has
been trading at a range between $6.06 and $23.76.
ERF is in the Oil & Gas Production industry, part of the Energy sector.