struggles

Associate 1 in IB - Cov

Agreed. Totally unfair! Unfortunately, the way the world works is if you never ask you'll never get what you want. If others are asking and you keep your head down, guess who will get chosen. 

You should email your staffer and cc your group head (if your staffer knows they're being watched, they won't be able to play favorites). Explain that you're worried working on IPOs will leave you unprepared for buyside recruiting and politely ask if you can be considered for the next M&A mandate. Tell them you appreciate the opportunity and all their guidance and be as nice as possible, but be sure to mention your goal of preparing for the buyside.  

I wouldn't go to this extreme of cc'ing a group head. I'd just swing by your staffer's office and say that I haven't gotten to do any M&A work, would it be possible for my next couple of staffings? If that doesn't move the needle then I'd just ask the group head about it if you continue to get the same assignments. Also, in my experience major IPOs (are there any that aren't anymore?) are good for the resume, not that I ever had any (BB sponsors and then LMM tech), but it seems that a lot of my friends got good play out of them, even if they were marginally on the deal.