Banking folks are vengeful, esp banks like HSBC. I heard that people don't share their prospective employer because previous colleagues/bosses bad mouth you and jeopardize your move. The BFSI circle is very small and close-knit too, whereas consulting is much friendlier and encourage leaving for better opportunities.
Are they retaining you because they like you and your work personally or because they are controlling attrition and they have a huge dependency on you?
If it's the latter, they will hire folks, ask someone to shadow you over next 4-8months and reduce your bargaining power during next appraisal.
Stay back if you trust and like your boss a lot and vice versa and if they offer good terms to show that like matching your hike or appraisals.
Also, they are cruel and planned when it comes to restructuring & layoffs. I try not to be the most expensive employee to them in case they are looking for headcount reduction.