More upside seen in Century Aluminum

Century Aluminum is pushing higher, and one trader is looking for the gains to continue.

optionMONSTER's Heat Seeker monitoring system detected the purchase of 10,000 December 14 calls for $0.80 and the sale of an equal number of December 12 calls for $1.61. Volume was below open interest in the lower strike, indicating that a long position was rolled to the higher strike.

CENX rose 6.57 percent to $12.65 on Friday. The aluminum producer lost more than half its value between January and the summer amid weak demand and excess capacity in the industry. But since bottoming out in early July, it has rallied more than 40 percent.

The shares closed the week above their 200-day moving average for the first time since mid-May, which some chart watchers may consider bullish sign.

Selling the December 12 calls and buying the December 14s let the investor recover about $0.81 of capital while maintaining long exposure to further gains. Such a strategy is commonly used to take profits and manage risk.

The transaction pushed total options volume in CENX to 14 times greater than average, with calls accounting for a bullish 96 percent of activity.