The ILF offers courses in finance and economics in addition to banking and finance law. The course is designed in way that even graduates from business background can pursue it. It attempts to bring law and business graduates on the same page.
First Person Accounts: Pallavi Railkar on the LL.M. at Columbia Law School
I recommend gaining some experience before an LLM degree. It also gives you clarity about your interest areas which helps you to design your LLM program accordingly.