From ER internship experience to IB internship/full-time position

Hey guys,

I am currently doing my master's in Finance in London and I would like to apply for a couple of Investment Banking internships or full-time positions after graduation. My problem is now that I don't have any internship experience in IB (4 internships - 1 in Financial Services Consulting, 2 in Equity Research and 1 in Finance & Accounting in an oil & gas company). I am currently trying to write a convincing cover letter but can't really think about any good arguments about why I want to transition from ER into IB or basically why I want a job in IB despite my experiences in ER.

Do you guys have any good arguments or suggestions what I could write?

Thanks in advance and enjoy your weekend!!