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

Seadrill Limited Ordinary Share (symbol: SDRL) was one of the worst losers
of the trading day today (2017-01-31), losing -29.7%. The number of shares
that changed hands was 50,291,482, or about 5 times the average daily
volume in the stock.
The closing price was $1.87, amounting to a market cap of $943,310,000,
about -75.03% off the highest price in the last 12 months. The stock has
been trading at a range between $1.57 and $7.49.
SDRL is in the Oil & Gas Production industry, part of the Energy sector.