Go to gov.uk and look for Tier 2 list of sponsors. If the company you would like to work for is in this list you can apply and state that you will need sponsorship. There are multiple other requirements, but those are easy to satisfy if you are into asset management or corporate tech. The only potential problem is labour market test, which your prospective employer has to carry out in order to prove they can't find anyone for this role 1. in the UK 2. in the EU (but again, this is more a 'tick' in the list than a real test).