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

Imperva, Inc. Common Stock (symbol: IMPV) was one of the worst losers of
the trading day today (2016-10-19), losing -15.97%. The number of shares
that changed hands was 8,995,120, or about 11 times the average daily
volume in the stock.
The closing price was $39.2, amounting to a market cap of $1,280,000,000,
about -49.74% off the highest price in the last 12 months. The stock has
been trading at a range between $31.11 and $77.99.
IMPV is in the Computer Software: Prepackaged Software industry, part of
the Technology sector. It first went public in 2011.