Shipping company keen for pay-off (6)
I believe the answer is:
upshot
'pay-off' is the definition.
(both can mean the end result of something)
'shipping company keen' is the wordplay.
'shipping company' becomes 'UPS' (United Parcel Service).
'keen' becomes 'hot' (I've seen this in other clues).
'ups'+'hot'='UPSHOT'
'for' is the link.
(Other definitions for upshot that I've seen before include "anti-aircraft fire?" , "One killed the albatross" , "issue" , "increased exposure" , "Eventual outcome or conclusion" .)