Obligations best sorted out at the trading centre (5)
I believe the answer is:
debts
'obligations' is the definition.
('debt' can be a synonym of 'obligation')
'best sorted out at the trading centre' is the wordplay.
'sorted out' indicates anagramming the letters.
'at' means one lot of letters go next to another (I've seen this in other clues).
'centre' means to look at the middle letters.
The middle letter of 'trading' is 'd'.
'best' is an anagram of 'ebts'.
'ebts' put after 'd' is 'DEBTS'.
(Other definitions for debts that I've seen before include "Liabilities" , "They're owed" , "Financial obligations" , "Amounts owed" , "Outstanding sums" .)