Mini Perm

What Does Mini Perm Mean?
Short-term financing used to pay off income-producing construction or commercial properties, usually payable in three to five years.

Investopedia explains Mini Perm
In this case, "perm" is short for "permanent", alluding to permanent financing. Mini perm financing is something a developer would use until a project has been completed and can therefore start producing income. In other words, a developer will use this type of financing prior to being able to access long-term financing or permanent financing solutions.