accounted for almost all the volume: The March 41 puts were bought for $1.29 the March 38 puts were sold for $0.14. Volume was more than triple open interest in both strikes.

This bearish put spread cost $1.15 to open and will earn a maximum profit of 161 percent if the AMJ closes at or below $38 on expiration. It ended yesterday's session at $40.56, up 0.02 percent. (See our Education section)

The AMJ has been drifting higher as investors flock to the rich dividend yields of pipeline companies. Many of them are structured as Mastered Limited Partnerships, which create potentially troublesome K-1 tax forms. The appeal of AMJ is that it transforms this income stream into an ordinary interest that's reported on a 1099 form.

Given how much it has appreciated, yesterday's spread appears simply to be a hedge against a potential pullback. Puts outnumbered calls in the session by 588 to 1, according to the Depth Charge.

More From optionMONSTER

• Bulls look for Riverbed to move
  
• What's behind huge Weatherford bet
  
• Bulls see Timken near all-time highs