Sector is the classification field identifying sector for reporting, underwriting, or workflow routing. It should use controlled master values instead of free text. Define valid values, source, and regulatory or policy relevance. In underwriting, it provides business and banking context that supports facility structuring, risk assessment and credit-decision documentation. The field should be supported by documentary evidence and should remain consistent across application data, KYC records and regulatory reporting. For example, the underwriter may use it to understand borrower behaviour, facility need, banking arrangement and the quality of supporting documents. It matters because the same borrower can look different depending on banking arrangement, transaction behaviour, documentation quality and business context. The common caution is to document the source, date, assumptions and credit impact so the term does not become a vague narrative label.