People do an MBA after years of working,and either use it as a step for their resume(or a fresh start from someone looking to go into the business side who has a non-commerce degree),or the firm wants the person to take on more of a management role in the future, and the MBA better qualifies them for it. It doesn't really look good at all to get an MBA without experience,plus they use many examples from the workplace,so experience helps understand some of the teaching. If you're wanting to do a degree after your bachelors, then it would be a master's degree. But i suggest you go into a grad program and get some work experience under your belt before attempting any degree after you finish your bachelors(because firms then tell you that you're overqualified with a master's if you apply for their normal grad programs,with no experience(same as rish said with the MBA).
Take note that if you start becoming disinterested in your engineering degree you'll also typically start to do worse in it which pulls your WAM down, and you'll need at least distinction-high distinction(depending on your other merits) to even get a interview at an IB firm, so don't let eng drag you down.
And what Rish said.^ good advice
