Lender’s eligibility making banks dirt poor (6,6)
I believe the answer is:
credit rating
'lender's eligibility' is the definition.
The definition suggests a singular noun which matches the answer.
'making banks dirt poor' is the wordplay.
'making' becomes 'creating' ('create' can be a synonym of 'make').
'banks' means one lot of letters goes inside another (bank can mean to surround or border).
'poor' indicates anagramming the letters.
'dirt' anagrammed gives 'ditr'.
'creating' enclosing 'ditr' is 'CREDIT RATING'.
Can you help me to learn more?
(Other definitions for credit rating that I've seen before include "loan may depend on it" , "justification for advance" , "Trust able seaman" , "lender's assessment" , "Estimate of person's financial trustworthiness" .)