Those who look after business propositions (7)
I believe the answer is:
tenders
'those' is the definition.
I can't tell whether this definition defines the answer.
'look after business propositions' is the wordplay.
'look after' becomes 'tend' (tending is a kind of looking after).
'business propositions' becomes 'ers' (I can't explain this - if you can you should give a lot more credence to this answer).
'tend'+'ers'='TENDERS'
'who' is the link.
Can you help me to learn more?
(Other definitions for tenders that I've seen before include "Supply ships" , "Offers to do work for a stated amount" , "Dinghies towed by ships" , "They provide supplies to other ships" , "Bids" .)