Bearish speculation has picked up steam on Alcoa Inc. (NYSE:AA - 9.18) in recent weeks, with option players buying puts at an accelerated clip. In fact, the blue chip has already seen roughly 13,000 puts change hands so far today, more than tripling its average intraday put volume.

Upon closer inspection, the January 2013 7.50-strike put is most active today, with nearly 2,900 contracts exchanged. All of the puts crossed at the ask price, and implied volatility was last seen almost 2 percentage points higher, hinting at buy-to-open activity.

By purchasing the puts to open, the buyers have one of two goals: to profit from a short-term retreat, or to "insure" a stock position. In the case of the former, the buyers are expecting AA to breach the $7.48 level (strike minus volume-weighted average price of $0.02) within the next couple of weeks -- which encompasses Alcoa's unofficial kickoff to earnings season. In the case of the latter, the traders are locking in an acceptable sale price for their AA shares, should the stock take a tumble in the near term.

Whatever the motive, today's appetite for puts merely echoes the growing trend seen on the major options exchanges. On the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX), speculators have bought to open more than five AA puts for every call during the past two weeks. What's more, the security's 10-day put/call volume ratio of 5.18 ranks in the 93rd percentile of its annual range, suggesting option buyers have initiated bearish bets over bullish at a near annual-high pace.

At last check, AA has added 1.2% to flirt with the $9.18 level. Historically, the company has surpassed the Street's bottom-line earnings estimates in three of the past four quarters, according to Thomson Reuters. This go-round, analysts, on average, are anticipating a fourth-quarter profit of 7 cents per share.