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

Transdigm Group Incorporated Tr (symbol: TDG) was one of the worst losers
of the trading day today (2017-01-20), losing -9.87%. The number of shares
that changed hands was 8,690,296, or about 14 times the average daily
volume in the stock.
The closing price was $226.9, amounting to a market cap of $12,100,000,000,
about -22.92% off the highest price in the last 12 months. The stock has
been trading at a range between $180.76 and $294.38.
TDG is in the Military/Government/Technical industry, part of the Capital
Goods sector. It first went public in 2006.
Looking at its valuation, the stock is now trading at 21.84 times earnings.