MBA

There are several departments in a firm. Expertice in one cant help you survive all. So take a field based on your firm.

Suppose your starting a financing company then you must have finance degree to run your firm with minimum risk.

Suppose you have a lot of skilled works then you need Human Resource to tackle them. 

Suppose you need to sell your products or service, then you need marketing degree to tackle competition.

Rest of the degree go deep in the management.  I think that wont be necessary for you. So choose a dual field based on your company needs. Best of luck. 

hii... Welingkar institue of Management has a course called 'Business Management for Legal Professionals' I hope it helps you. Good Luck.