Accepted top-tier bank offer, then unexpectedly got another offer I prefer before starting

Hi everyone,

Looking for some advice from people who may have been through something similar.

A few months ago, I accepted and signed an offer with a top-tier investment bank in London. My start date is in a few months.

Since then, I unexpectedly received another offer from a different top-tier investment bank in London. After going through the process, I believe this second opportunity is actually a better fit for me in terms of the team and the type of work, so I’m seriously considering accepting it.

The complication is that I’ve already progressed quite far with the first bank:

• Employment contract signed.
• Mandatory regulatory exams have been arranged, and I’ve already received access to all the study material and learning platform.
• The work visa process has been initiated, although I haven’t yet submitted the formal application.
• I obviously haven’t started working yet.

My questions are:

1. Has anyone here (or someone you know) accepted a second offer after already signing a first one, but before their start date?
2. How did the first bank react? Was the bridge completely burned, or was it handled professionally?
3. Does the visa process materially complicate things if the application hasn’t yet been submitted?
4. Are there any legal or contractual considerations I should be aware of beyond the obvious reputational aspect?
5. Is this something that occasionally happens in banking, or is it generally considered a major red flag?

For context, this isn’t about compensation or prestige, both firms are at a very similar level. It’s simply that the second opportunity aligns more closely with the type of team and work I’d ideally like to build my career around.

I’d really appreciate hearing from anyone who’s experienced this personally or knows someone who has.

Thanks!