Yes. I think of it analogous to a spring. It should like someone holding a stretched spring . If I hold the loop with my hands (not allowing it to move), it is like a stretched spring and must have extra stored energy in it. So that energy must be its potential energy. And when I leave it, it returns to horizontal position where its potential energy must be zero.
But its not correct. We know the potential energy at the position shown is zero and that is maximum in the position where torque is zero. Please explain me why.
The correct values for potential energy can be explained by u=-IABcos theta, but I need a general explanation.

And what is the need of the minus sign in this formula?

I did some thinking on this. Maybe the potential is like Celsius for temperature. Anything at 0 degrees Celsius has internal energy. Similarly this loop at 0 potential can still do work by going to negative potential... Am I right?