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

Patterson-UTI Energy, Inc. (symbol: PTEN) was one of the worst losers of
the trading day today (2015-09-30), losing -5.4%. The number of shares that
changed hands was 6,211,819, or about 1 times the average daily volume in
the stock.
The closing price was $13.14, amounting to a market cap of $1,910,000,000,
about -61.0% off the highest price in the last 12 months. The stock has
been trading at a range between $12.97 and $33.69.
PTEN is in the Oil & Gas Production industry, part of the Energy sector. It
first went public in 1993.
Looking at its valuation, the stock is now trading at 30.63 times earnings.