With crude-oil futures perched at a six-week low, option speculators are trying to score some quick profits. Put volume is running about five times ahead of normal on the Market Vectors Oil Services ETF (NYSEARCA:OIH - 41.95) today, with the ETF trading down about 1.3%. Since last Friday, the OIH has dropped 4.3%, and put buyers are hoping for more of the same for the balance of the week.

The September 42-strike put -- at the money and expiring at Friday's close -- has seen roughly 29,000 contracts trade today, on open interest of less than 9,000. Several large blocks have traded off the ask price (for an average of $0.32 per contract), and implied volatility has expanded by 1.6%. This all suggests investors are buying these puts to open, with the hopes the ETF will fall south of the 42 strike in the next couple of days, and will continue to drop, taking out the breakeven price of $41.68.

Below the breakeven point, gains are unlimited down to zero for the life of the option. If the ETF is trading above the strike price when Friday's closing bell sounds, the traders stand to lose 100% of the premium paid.

Here are some additional articles of interest:

• Commodities Review: For the Week Ended September 17, 2012


• Option Volume Briefs: Gold Speculators Extend Their Bet