Stock tokens and reserves
A stock token is an ERC-20 token on Arc that references a listed stock, for example NVDA.sol (token name "Solon NVDA").
Backing
- One stock token corresponds to one unit of the native Robinhood Chain stock token held in the reserve vault. Both tokens use 18 decimals.
- Only the stock hub can mint or burn stock tokens. The stock hub mints only against a settlement result that carries proof from the reserve vault. The stock token contract has no owner.
- The reserves are held by the reserve vault contract on Robinhood Chain, not by an operator account.
- Stock can leave the reserve vault in only two ways: a verified sell order, or a delivery through the official bridge. No administrator function exists to withdraw backing stock.
- Stock tokens are tokens. They are not shares of a listed company and do not confer shareholder rights.
Listed stocks
| Stock | Stock token | Issuance limit |
|---|---|---|
| NVIDIA | NVDA.sol | $400,000 |
| Apple | AAPL.sol | $300,000 |
| Tesla | TSLA.sol | $300,000 |
Issuance limits are governance parameters. The guardian can lower a limit with immediate effect. An increase passes through the 48-hour timelock and then a further 48-hour delay, so it takes effect no earlier than 96 hours after it is submitted.
Prices
- Prices are sourced from Chainlink price feeds on Robinhood Chain and relayed to Arc. The relayer determines only which stocks are relayed and when. It cannot supply or alter a price.
- Price feeds stop updating while the market is closed. A price that has not been updated for 26 hours, for example over a weekend, is treated as stale.
Proof of reserves
Anyone can verify the reserves as follows:
- On Arc, call
totalSupply()on the stock token.supplyOf(underlying)on the stock hub returns the same value. - On Robinhood Chain, call
reserveOf(underlying)on the reserve vault. - Coverage ratio = vault holdings ÷ supply on Arc. "Fully covered" means that the holdings are greater than or equal to the supply.
The reserve vault also exposes entitledOf, backingOf, isFullyBacked and porSnapshot. These views include amounts in transit: stock that has been purchased but not yet minted on Arc, and stock tokens that have been burned but not yet delivered.
The Proof of reserves page shows each figure together with the corresponding cast call command and the block number at which it was read.
Proof of reserves covers on-chain token reserves only. It does not verify that the issuer of the Robinhood Chain stock token holds the underlying shares.