Time limit for issuing tax invoice: service suppliers must issue invoices within prescribed periods; exceptions for insurers and banks. Rule 47 sets a time limit for issuing tax invoices for supplies of services: ordinary suppliers must issue invoices within thirty days of supply, while insurers, banking companies and financial institutions are allowed a longer issuance period. Additionally, insurers, banks, financial institutions, telecom operators and other government-notified classes supplying between distinct persons may issue invoices when recording the supply in their books or before the quarter's end, providing an alternative quarterly issuance option.