What's left of rise may be owing (7)
I believe the answer is:
residue
'what's left' is the definition.
(residue means what's left behind)
'rise may be owing' is the wordplay.
'may be' is an anagram indicator.
'owing' becomes 'due' (similar in meaning).
'rise' is an anagram of 'resi'.
'resi'+'due'='RESIDUE'
'of' acts as a link.
(Other definitions for residue that I've seen before include "Lees, dregs" , "What's left" , "Remainder, leftover" , "Whatever is left over" , "Remains to be seen" .)