um...maybe as Actuaries?
Sorry I don't understand your question...it's like asking "What role do cleaners have at Investment Banks?" Er...Cleaners?
Pay I assume is consistent with other operations professionals/market rates, maybe a tad more because IBanks typically want more hours out of you so pay you more.
EDIT: oh I think do you mean what they do as actuaries for ibanks? I'm not sure. I haven't heard of many actuaries being employed by IBanks. They tend to work for Actuarial Consulting firms, Accounting firms and also commercial Banks and Insurance companies more.