Hi and Welcome to GMAT Club!
I don't think having a Masters/CFA should be a big disadvantage to the MBA application process but at least one person did mention that there is a bit of a challenge potentially for IB -
here is that post. You may want to ask this question to folks who are already in IB. There is an investment monkey website/forum that has quite a few IB monkeys on it

and they may have a bit more clarity about the IB and how it fits with CFA/Masters.
On the MBA side, I would say you do want to explain why you are getting an MBA and why your MSc was not quite cutting it. One sentence may be sufficient but it could be a question on the AdCom's mind though with most people doing MSc right out of undergrad, that decision is usually done in a vacuum and does not compare to the MBA (at least most BSchools want you to think that

)
onedaypm
Hi All,
I received my undergrad in Accounting and Finance 4 years ago and then dived immediately into an MSc in Finance from Imperial College in London. After graduating i started working as a risk analyst for an asset manager and moved to one of the biggest US asset managers in London 6 months ago, still as a risk analyst. I have been also pursuing the CFA which i thought would help me in my career and i am almost done with it.
My question is this: I want to move to the US and work in Investment Banking. The best way to do that is i believe through an MBA in the top US MBA Business schools. Do you think my profile would be disadvantaged by my credentials (already a masters + CFA) , neutral or actually these could benefit me?
Thank you.