Collocations for auditor - noun

company, company's
internal
external, independent, outside
county (AmE), district, government (BrE)
The council and district auditors have agreed that the deals were unlawful.

appoint (BrE), hire (AmE)

auditor of
She is one of the nation's leading auditors of public companies.

auditor to (BrE)
His firm has been appointed the auditors to the company.

an auditors' report