Macroshares Oil Down (DCR 1.15) is an ETF that was designed to allow stock investors to play the downside in oil. However, the fund is closing on June 25, as oil has stayed above $111 for three days in a row. So the "ETF" terminates on June 25 with it's NAV being distributed along with a dividend of about 8 cents.
The NAV is determined by dividing the price of oil by 3, and subtracting it from 40. Thus the NAV will be zero if oil stays above $120. (40-120/3=0). If oil would drop to $110, it's NAV would be 3.33. (40-110/3=3.33). In effect, this a put option on oil for a month.
It's probably a play as a trade since oil looks to have made a short term top and is rolling over. Somehow, I don't think all the oil bulls in the pit will buy with all the government threats and calls of increased margin requirements amongst the talk of oil price gouging and hoarding.
They'll play where it isn't such a battleground.