United States Natural Gas Fund, LP

According to their filing with the SEC to date USO has not entered into any agreement with any FCM other than RBC and it cannot predict with any certainty when it will do so.

Now, USO's sister product, the United States Natural Gas Fund, which ticker is UNG, did experience similar but lesser stresses in the summer of 2009.

First, what's happened is that its AUM exploded, a little bit like what happened with USO.

Then it started experimenting with exotic instruments.