Basket and NAV feed

SlateBasket is an ERC-20 backed by fixed amounts of its constituents. SLATE-5 on Robinhood Chain testnet holds TSLA, AMZN, AMD, PLTR and NFLX, set at $10 of each per share when it was first created.

In kind, price-independent

function create(uint256 shares, address to, uint256[] calldata maxAmounts) external returns (uint256[] memory);
function redeem(uint256 shares, address to, uint256[] calldata minAmounts) external returns (uint256[] memory);
function quoteCreate(uint256 shares) external view returns (uint256[] memory);  // rounded up
function quoteRedeem(uint256 shares) external view returns (uint256[] memory);  // rounded down

Creating takes each constituent pro rata to what the basket already holds; redeeming pays out pro rata. Neither reads a price, so no oracle failure can mint or drain the basket. Rounding always favours the basket, the first creation locks MINIMUM_SHARES (10⁶ wei) at the dead address so the supply never returns to zero, and delivery is checked by balance difference.

Fuzz invariants in the test suite: backing per share never decreases, and a create-then-redeem round trip never profits.

The NAV is a feed

SlateNavFeed publishes NAV per share as an AggregatorV3Interface, 8 decimals:

NAV per share = Σ holdingᵢ × priceᵢ / totalSupply

where priceᵢ is each constituent's SlateFeed price (multiplier already applied). Its status is the worst of the constituents' and its observation time is the oldest. One stale, paused or mid-split stock makes the whole NAV unavailable, so a lending market that accepts SLATE-5 as collateral inherits every SlateFeed guard with no extra code:

AggregatorV3Interface nav = AggregatorV3Interface(0x8E2b6C63463DCf51b307811dB41bd60d7987608D);
(, int256 navPerShare,,,) = nav.latestRoundData(); // reverts unless every constituent is usable

The constructor checks that each feed's token() matches the constituent at the same index, so a basket cannot be wired to the wrong feeds.

Composition

Fixed composition, equal value at creation. Weights drift with prices. Rebalancing is v2: it needs a price to act on, and in-kind create and redeem deliberately never use one.