JPMorgan Cazenove is being circled by headhunters and rival banks as the two-year lock-in agreements struck when the US giant and the British blue-blood firm merged come to an end next month.
Executives at rival banks said they had already approached both individual bankers and whole teams about leaving.
"People have the date in their calendar," said Pablo Guerra, a partner at the City headhunting firm Glocap.
Bonus season is always a heavy poaching period. In addition to its February round of bonuses, Cazenove's long-term incentive plan entitling employees to share packages expires next month.
"There's a general awareness that the original deal was done with a significant lock-in, which expires soon. That makes it a different dynamic than for most other firms," Mr Guerra said. Another source said: "The feeling within the firm is that a lot of the senior guys are going to leave."Reuse content