US Universities

It's mainly a holistic approach from both your essays, a-level and gcse results/predictions, references, SAT/ACT results and a whole bunch of other things.

So what a levels would you recommend to give me the best chance of doing a finance degree at a top uni

So what a levels would you recommend to give me the best chance of doing a finance degree at a top uni

For a finance degree, Maths, FM and Economics, as indicated in the answers above, would be a good combination for A-Levels. It might be a good idea to do a fourth one (maybe from the sciences or history, depending on your interests) but it is not necessary.

The SAT is not the only important thing, but it is very very important nevertheless. So I would concentrate on that as much as the A-levels. Ideally you should aim for a score above 1500 to be a strong candidate for very top universities, but a score above is 1400 is generally okay. You could also take the ACT, so it might be a good idea to do mock tests of both and see which one you feel more comfortable with.

Another important thing would be to take 2 or 3 of the SAT IIs (SAT Subject tests). Some unis require them, so you should check for specific requirements. These results are also important, and for finance I would definitely recommend taking Math II as one of them.

Also do not neglect your essays and extra curricular activities, US unis take almost everything into account. It would be a good idea to have some extra-curriculars related to finance.

If OP is applying to unis that state the SAT subject Tests are "recommended" or "optional" there is no point in doing them, imo they are a waste of time. I did Literature and Math 2, didn't send off my scores and still got accepted