F5 Networks (NASDAQ: FFIV) -- implied volatility collapses on EPS; FFIV rallies 20%. FFIV, a provider of content switching application traffic solutions, is recently up $13.06 to $79.22. WEDB says "Q2 exceeds expectations; continued growth to come." FFIV May option implied volatility of 34 is below its 26-week average of 42 according to Track Data, suggesting decreasing price fluctuations.

Jeffries Group (NYSE: JEF) -- option implied volatility Up to 42; on speculation Risk. JEF, an investment bank engaged in financial product execution services and asset management, is recently up 08 cents to $30.19. JEF has been frequently mentioned as a takeover target. JEF call option volume of 2,194 contracts compares to put volume of 231 contracts. JEF May option implied volatility of 42 is above its 26-week average of 31 according to Track Data, suggesting larger price risks.

United Rentals (NYSE: URI) -- implied volatility & volume increases into EPS & on speculation. URI, the largest equipment rental company in the world, is recently up 96 cents to $33.69. URI will report EPS on 5/3. URI call option volume of 2,347 contracts compares to put volume of 406 contracts. URI May 35 calls are bid 75 cents above its theoretical value of 35 cents. URI May & June option implied volatility of 38 is above its 26-week average of 35 according to Track Data, suggesting slightly more risk.

Option volume leaders today are: Apple Inc. (NASDAQ: AAPL), Amazon.com Inc. (NASDAQ: AMZN) and Qualcomm Inc. ( (NASDAQ: QCOM).