Public offer classification governs when multi-recipient offers are deemed public; limited private issues require dematerialised transfers and depository mechanism. Regulation 21 applies to public offers of securitised debt instruments, treating offers to any section of the public as public offers but excluding offers that are confined to recipients or are otherwise domestic. Offers to fifty or more persons in a financial year are deemed public, with the non-public exception limited to instruments of the same tranche that are pari passu. Special purpose entities may avoid public offer status by expressly limiting investors to fifty, mandating dematerialised issuance, holding and transfer, and using the depository's issuance, allotment, holding and transfer mechanism. 'Financial year' means the twelve months commencing 1 April.