ankrETH

ankrETH is Ankr's reward-bearing staked-ETH token whose ETH value grows over time.

ankrETH is Ankr's reward-bearing staked-ETH token whose ETH value grows over time. No direct ankrETH/USD Chainlink feed is used; this ICustomPriceFeed adapter inverts the token's ratio() and applies an ETH/USD price read from the NAV's own primary feed.

The ETH/USD term is sourced from the NAV's own selector — see Base/USD from the NAV's own selector.

Source: ankrETH_CustomPriceFeed.sol

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Approach

ETH/USD ÷ ratio() — ratio() is ankrETH-per-ETH, so its inverse is ETH per ankrETH.

ankrETH price feed — how its oracle inputs compose into a USD price, with the staleness gate.

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Price calculation

price = (ETH/USD) (8) × 1e18 / ratio() (18)      // USD, 8 dec

Input	Source	Description
ratio	IankrETH.ratio() on ankrETH (18 dec)	ankrETH per 1 ETH (decreases as rewards accrue)
ETH/USD	NAV base — getPriceDataNoDivergence(WETH) (8 dec)	the NAV's primary WETH/USD price, the numerator

Because ratio() is ankrETH-per-ETH, ETH-per-ankrETH = 1e18 / ratio; the 1e18 numerator cancels the ratio's 18-decimal scale, leaving the ETH/USD feed's 8 decimals. As staking rewards accrue, ratio() decreases, so the derived ankrETH price rises. Output decimals are inherited from the ETH/USD feed (8).

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Constructor

constructor(
    address ankrEth_,
    address nav_,
    address baseAsset_
)

Parameter	Description
ankrEth_	ankrETH token address (also the supported underlying)
nav_	NAVCalculator (proxy) — supplies the base asset's USD price via getPriceDataNoDivergence
baseAsset_	The registered base asset whose USD price is read (WETH)

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Staleness

getLatestPrice() returns stale if ratio() returns 0, or if the NAV reports the base asset (WETH) stale — all its feeds stale. The base leg's updatedAt comes from the NAV's selected WETH feed. The ratio() call has no independent heartbeat.

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Chains

Deployed on Ethereum.