Spanish location in Iberia’s foremost business area (5)
I believe the answer is:
ibiza
'spanish location' is the definition.
(Spanish island)
'iberia's foremost business area' is the wordplay.
'foremost' says to take the initial letters.
'business' becomes 'biz' (biz is a kind of business).
'area' becomes 'a' (maths abbreviation).
The first letter of 'iberia' is 'i'.
'i'+'biz'+'a'='IBIZA'
'in' acts as a link.
(Other definitions for ibiza that I've seen before include "holiday venue" , "Westermost of Balearic Islands, popular for holidays" , "Clubbers' island" , "One of the Balearic Islands" , "One of matching pair" .)