I will post various color treatments right away.
Unfortunately, I have to be honest, risking my high ranks in the contest. But that is not as important, as I see the financial spark in the logos also. Gold really gives it a little bit of that feeling. But so does the columns - they are often associated with banks too. But that should not bother you, there are so many symbols around the world, used in almost every field.
My initial intention of using gold is, that it looks straight, very contrast, catches the eye of the observer, also, in my opinion, leaves the feeling of stability.
I will try silver or any metallic look, as well as other gradient colors resembling rock for example, but also other, non-related to anything colors, that would give you flexibility.
I am jumping up and down knowing, that you like what I do - that is the best prize for a designer.