Coinbase B20

In plain English: B20 is the token format Coinbase uses for its tokenized stocks on Base.

B20 is the Base-native token standard that Coinbase’s tokenized stocks use (Base; Base docs). It is designed to work for any asset; stocks are one use case.

Design

• A superset of ERC-20, built as Rust precompiles and shipped in Base’s Beryl upgrade (Base docs). Standard ERC-20 methods and events work.
• Two variants: Asset (6-18 decimals, with a multiplier) and Stablecoin (6 decimals) (Base docs).
• Built-in controls: transfer policies, freeze-and-reissue, roles, memos, supply caps and permit (Base docs).
• Audited by Base and Spearbit, per the docs (Base docs).

Tokenized stocks on B20

• Multiplier: one token does not always equal one share. Cash dividends are converted to shares and the multiplier rises (e.g. 1.02) (Base docs). Scheduled changes use ERC-8056 updateUIMultiplier; the instant updateMultiplier is deprecated and kept as a failsafe.
• Identification: integrators should identify tokens by contract address, not ticker, and watch the B20Created event. A public, keyless API returns addresses, supply, multipliers, ISINs and Chainlink reference values (Base docs).
• Access: secondary transfers are permissionless; KYC applies to Authorized Participants who mint and redeem (Base docs).

See Coinbase tokenized stocks, corporate actions and ERC-3643 for a permissioned alternative.

Sources

Public originals for the facts on this page.

• https://blog.base.org/tokenized-stocks
• https://docs.base.org/upgrades/beryl/b20
• https://docs.base.org/build-on-base/integrate-defi/list-tokenized-stocks