Verifies scam by companies (8)
I believe the answer is:
confirms
'verifies' is the definition.
(I've seen this in another clue)
'scam by companies' is the wordplay.
'scam' becomes 'con' (both can mean a fraudulent scheme).
'by' says to put letters next to each other.
'companies' becomes 'firms' (I've seen this in another clue).
'con'+'firms'='CONFIRMS'
(Other definitions for confirms that I've seen before include "Corroborates" , "Provides support for the truth of" , "Supports the truth of something" , "Finalises or makes definite" , "Provides supporting evidence of the truth" .)