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

Patterson Companies, Inc. (symbol: PDCO) was one of the worst losers of the
trading day today (2016-11-22), losing -16.73%. The number of shares that
changed hands was 14,683,410, or about 13 times the average daily volume in
the stock.
The closing price was $39.56, amounting to a market cap of $3,780,000,000,
about -21.51% off the highest price in the last 12 months. The stock has
been trading at a range between $36.46 and $50.4.
PDCO is in the Medical Specialities industry, part of the Health Care
sector. It first went public in 1992.
Looking at its valuation, the stock is now trading at 19.51 times earnings.