Minimum subscription requirement for public debt issues set with refund, oversubscription retention limits and enhanced prospectus disclosures. SEBI mandates a 75% minimum subscription of the base issue size for public debt issues, sets a minimum base issue size, caps retention of over-subscription generally at 100% of the base size (with shelf and tax-free bond exceptions), requires refunds with interest for unmet minimum subscription, and prescribes enhanced prospectus disclosures including granular allocation of issue proceeds, a 25% cap on general corporate purposes, NBFC-specific lending disclosures, and specified additional clauses and certifications in the offer document.