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

Cliffs Natural Resources Inc Co (symbol: CLF) was one of the worst losers
of the trading day today (2016-04-20), losing -6.16%. The number of shares
that changed hands was 12,449,157, or about 2 times the average daily
volume in the stock.
The closing price was $4.42, amounting to a market cap of $677,480,000,
about -35.66% off the highest price in the last 12 months. The stock has
been trading at a range between $1.2 and $6.87.
CLF is in the Precious Metals industry, part of the Basic Industries sector.