It depends on the market (and on what position in IB you are interested in).A couple of years ago, I-banks were happily hiring MBAs because the market was good and they were desperate for talent. Today, when the market is looking down, you need as much direct IB experience and qualifications as possible, so CFA would be more valuable. In 3-5 years time after your time at Bain and the MBA course, the market could be different again.CFA qualification is also a more important requirement for Fund Management (for example) than for M&A.The efinancialcareers website is useful for keeping on top of developments in the IB career marketplace.