Cameron International (CAM) is under pressure today, down $1.25 to $41.92. A day earlier, shares of the Houston-based oil driller lost $1.16 to $43.17 and put volume picked up to 4X the typical levels. About 5,000 contracts including lots of April 42.5 and 45 puts at the asking price in midday action. At the end of the day, open interest in the 45s had increased by 2033 and in the 42.5s by 1940. Looks like put buyers are opening positions as shares of CAM see two days of relative weakness. Implied volatility is up to 36, from about 34 two days ago.