One of the mysteries of the English language finally explained.
Definition of non-performing in US English:
non-performing
adjective
1That is guilty of failing to fulfil a promise, contract, obligation, etc. (rare).
2Designating or relating to a person affiliated with the arts but not involved in public performance. Also: denoting an art such as painting, sculpture, etc., which does not normally involve public performance by the artist.
3Finance. Of, relating to, or denoting an asset that is not producing the anticipated or contractually due income; especially denoting a loan whose borrower has defaulted on repayments. Frequently in "non-performing asset", "non-performing loan".
Origin
Mid 17th century; earliest use found in Faithfull Scout. From non- + performing.