ERC-3475 (Abstract Storage Bonds)

ERC-3475 originated in April 2021 (tracking issue ethereum/EIPs #3467) from the team linked to D/Bond, under the historical working title Multiple Callable Bonds Standard. Its defining trait is abstract on-chain storage, where the bond's metadata, values and conditions live inside the contract itself rather than relying on external storage. The official specification consulted for this revision is marked Final.

Its mechanism rests on two levels. Each Class ID represents a configurable bond type, and within each class every nonce identifies a specific issuance condition, with its own metadata, supply and redemption rules. The standard supports batched operations to issue, redeem and transfer, which lowers gas cost, and lets bonds be split and traded on secondary markets.

ERC-20, ERC-721 and ERC-1155 cannot natively express debt structures with tranches or variable redemption conditions. ERC-3475 models that complexity in a single contract, fitting structured fixed income and callable bonds on-chain. The reference implementation is D/Bond. One precision note matters: the most cited digital bond issuances, such as Siemens on Polygon or the European Investment Bank, use their own contracts, not ERC-3475. ERC-7092 (Financial Bonds) is a later standard addressing the same ground with a different approach.