ACA big 4 into investment banking

1. Level depends on how much experience you have. If you do your ACA and then leave soon after its likely analyst 3
2. Pay is exactly the same as other analysts at your level, as is bonus. Less data points on sign on, some places offer none, some offer same as graduates get, other may do more
3. Depends. Greenhill do a process which starts in September every year. Rothschild I think are now doing a process which starts in July every year. Other Banks are on an ad hoc basis, but i assume usually when people quit after bonuses would see more demand

AMA, I did this route a few years ago