Company investing in mine mixed up earnings (6)
I believe the answer is:
income
'earnings' is the definition.
(thesaurus)
'company investing in mine mixed up' is the wordplay.
'company' becomes 'co' (abbreviation).
'investing in' means one lot of letters goes inside another.
'mixed up' indicates an anagram.
'mine' with letters rearranged gives 'inme'.
'co' inserted into 'inme' is 'INCOME'.
(Other definitions for income that I've seen before include "Remunerations, takings" , "Money from investments or for work" , "Coin me! (anag)" , "Money received for work or from investment" , "Money received as wages, interest etc" .)