A model with oil fund

Dear Professor Pfeifer,
I am working on a model with an oil fund. The problem is oil funds are usually explosive (I mean the value is increasing every period), so we cannot imagine a SS for this variable. I was wondering if there is any solution for this problem in Dynare. I know you are pretty busy these days. I truly appreciate your time.
Kind regards,

It very much depends on how you think about the economic environment. The capital stock also grows every period, but there is a natural normalization (intensive form) that assures the model has a stationary representation.