Capping of ISINs for private placement debt securities limits ISINs maturing per year to enhance market liquidity. The circular caps ISINs for private placement debt securities to reduce fragmentation and boost liquidity by allowing a maximum of fourteen ISINs maturing per financial year per issuer, plus six ISINs for section 54EC capital-gains-tax debt securities. It bifurcates the fourteen into nine ISINs for plain vanilla securities (secured or unsecured) and five for structured/market-linked securities, permits three additional plain-vanilla ISINs where a specified outstanding threshold across nine ISINs is reached, applies to ISINs utilised from April 1, 2023, and requires exchanges and depositories to implement and monitor compliance.