Coal stocks are on the move this afternoon, and Arch Coal Inc (NYSE:ACI - 7.67) is no exception. Nevertheless, ACI put volume has spiked to roughly 12 times the norm, with 25,000 of these typically bearish bets exchanged thus far. For comparison, just around 15,000 ACI calls have crossed the tape.

Most of the action has transpired at the February 7 put, which has seen close to 21,300 contracts traded on open interest of fewer than 1,400, pointing to an influx of fresh initiations. In fact, nearly all of the volume crossed in one fell swoop, with a block of 20,000 contracts exchanged at the ask price of $0.25, suggesting they were bought.

By purchasing the puts to open, the buyers expect ACI to backpedal beneath the $7 level within the next several weeks. More specifically, the speculators will profit if ACI breaches the $6.75 marker (strike minus premium paid) by the closing bell on Friday, Feb. 15, when the soon-to-be front-month options expire. However, even if ACI remains north of the strike -- which has emerged as technical support during the past few weeks -- the buyers' risk is capped at the initial premium paid for the puts.

Broadening our sentiment scope, it seems today's appetite for short-term puts runs counter to the trend. The equity's Schaeffer's put/call open interest ratio (SOIR) of 0.56 indicates that calls nearly double puts among options slated to expire within three months. What's more, this ratio registers in the 14th percentile of its annual range, suggesting near-term traders are more call-skewed than usual at the moment.

Plus, as alluded to earlier, today's affinity for bearish bets comes despite ACI's upward momentum. At last check, the security has added 8% to wink at the $7.67 level, after Sterne Agee predicted a cyclical pricing rebound for coal in the second half of the year and into 2014.