Old, major player in financial services circles (4)
I believe the answer is:
orbs
'circles' is the definition.
(I've seen this before)
'old major player in financial services' is the wordplay.
'old' becomes 'o' (abbreviation).
'major player in financial services' becomes 'rbs' (I can't explain this - if you can you should give a lot more credence to this answer).
'o'+'rbs'='ORBS'
Can you help me to learn more?
(Other definitions for orbs that I've seen before include "sight" , "Ball shapes" , "They symbolise the power of kings" , "Lovely eyes, bros" , "Eyeballs" .)