Sirius XM (SIRI) sees serious call buying. Shares are down a penny to $1.80 and 23,000 call options traded on the stock, which is 3X the typical volume and compares to put volume of 820 contracts. Jan 2 calls, which are now 11.1 percent OTM and expiring in a three-and-a-half weeks, are the most actives. 11,000 traded. Mar 2, Jan 1, Jan14 $1, and Jan13 $4 calls on SIRI are seeing interest as well. Meanwhile, implied volatility is moving up to about 50, but with no recent company news to explain the high volume on the satellite radio operator today. Shares have been trading in a narrow range lately and are at the same levels today as two months ago.

*Scanning all single-stocks subject to 2500 contracts minimum call or put volume

Implied volatility in MolyCorp (MCP) is moving higher amid active trading in the options on the stock after China said it was keeping rare earth material export quotas unchanged in 2012. Supply concerns sent MCP down $3.5 to $28.5 per share. Jan 30 calls are the most actives on the stock. 2,675 traded. March 35 calls are the next most actives after 2,584 changed hands. Total volume is about 12,000 puts and 16,000 calls, and implied volatility jumped 19 percent to 70.

*Scanning all single-stocks subject to 2500 contracts minimum call or put volume

Biogen Idec (BIIB) loses 88 cents to $110.44 and options volume on the pharmaceutical maker is running 3X the daily average, being led by a 3000-contract block of Jan 70 puts bought for 10 cents to open on ISE. 4,034 now traded. The contract is 36.6 percent OTM with a -01 delta and expiring in 23 days. BIIB shares are up 64.7 percent year-to-date and has not traded for less than $70 per share since March.