Legacy Frax Dollar

frax
Rank #161•Stablecoins, USD Stablecoin, Crypto-backed Stablecoin
CoinYQ Dossier

Legacy FRAX: from fractional-algorithmic dollar to the frxUSD transition

FRAX is the original Frax stablecoin, launched on Ethereum in December 2020 under a fractional-algorithmic design. Frax later introduced frxUSD as a distinct reserve-backed successor; the documented 1:1 upgrade path applies to Ethereum FRAX, while the legacy token is stated to remain functional indefinitely.

FRAX V1 and the original mechanism

Frax's historical documentation dates the original launch to December 20, 2020 and describes a collateral ratio that dynamically rebalanced around FRAX's market price. The model combined collateral with an algorithmic component, with the under-collateralized portion represented through FXS mechanics.

That documentation now presents the V1 mint/redeem model for historical purposes and explicitly says it is retired. The historical mechanism should not be described as the current operating model of Frax's flagship dollar product.

The frxUSD transition and identity boundary

On January 2, 2025, independent coverage by The Block reported that Frax was launching the separate frxUSD stablecoin after governance approved BlackRock's BUIDL as a backing asset. Frax's own documentation describes frxUSD as a reserve-backed, multichain product, and its Ethereum address differs from the legacy FRAX contract.

FIP-419 defines the migration boundary precisely: Ethereum FRAX may upgrade to frxUSD 1:1, while Ethereum FRAX and sFRAX continue to function indefinitely. This is an Ethereum-specific documented path, not proof of a universal conversion rule for every chain or wrapped representation.

Current legacy operation and holder rights

The legacy Ethereum FRAX contract remains a distinct source-verified ERC-20. Etherscan's reviewed snapshot reports 219,320,045.872600381298337455 FRAX as max total supply; that figure is a dated state observation, not a permanent cap or a promise about future supply.

Holding FRAX establishes token possession and whatever protocol-level transfer or upgrade behavior is available on the relevant deployment. The cited materials do not establish direct ownership of reserve assets, a guaranteed yield stream, project revenue, or a legal claim against a named custodian.

Privileged controls and operational risk

Frax's legacy technical documentation says FRAX and FXS contracts have no pause or blacklist controls, while the verified ABI exposes owner/governance-controlled minting, pool administration, oracle setters, owner and timelock functions. Those are capability observations, not assertions about which address currently controls them.

The safe interpretation is deployment-specific: verify current owner, governance, timelock, pool and oracle addresses on-chain before relying on the control posture, and do not transfer the documented Ethereum-specific upgrade path to other chains without direct evidence.

How the project changed

  1. 2020-12-20
    FRAX V1 launches

    Frax's historical documentation dates the original FRAX launch to December 20, 2020 and describes its fractional-algorithmic collateral-ratio design.

  2. 2025-01-02
    frxUSD launch reported independently

    The Block reported that Frax was launching the distinct frxUSD stablecoin after governance approved BlackRock's BUIDL as a backing asset.

  3. 2025
    FIP-419 defines the Ethereum transition

    Frax governance's FIP-419 specifies a 1:1 Ethereum FRAX upgrade path to frxUSD while stating that Ethereum FRAX and sFRAX continue to function indefinitely.

  4. 2026-08-25
    Legacy Ethereum snapshot reviewed

    The reviewed Etherscan page identifies the verified FRAXStablecoin contract, 18 decimals, and a max-total-supply snapshot of 219,320,045.872600381298337455 FRAX.

Evidence and primary sources

Last evidence review: 2026-08-25

What is Legacy Frax Dollar?

FRAX is the original Frax stablecoin, launched on December 20, 2020. Its Ethereum-native token is the 18-decimal ERC-20 at 0x853d955aCEf822Db058eb8505911ED77F175b99e. Frax governance later launched frxUSD as a modernized successor: a distinct token intended to be backed by permitted cash-equivalent and tokenized Treasury reserves. FIP-419 documents a 1:1 upgrade path for Ethereum FRAX while stating that Ethereum FRAX remains functional indefinitely. FRAX should therefore be understood as a legacy asset in the Frax family, not as the current frxUSD contract.

What problem does Legacy Frax Dollar solve?

The original Frax design addressed the capital inefficiency of fully collateralized stablecoins by dynamically adjusting a collateral ratio around the dollar peg. When FRAX traded above $1, the V1 mechanism could reduce collateralization; when it traded below $1, it could increase collateralization. That mechanism is now documented as retired. The live Frax product focus is frxUSD, which addresses dollar-denominated settlement with a reserve-backed, multichain token and institutional-custody integrations.

How does Legacy Frax Dollar work?

Historically, FRAX V1 combined collateral with an algorithmic component and used a collateral ratio that responded to the market price; redemptions could return collateral plus newly minted FXS for the under-collateralized portion. The public legacy contract is source-verified and exposes owner/governance-controlled minting and pool administration, while the official documentation says FRAX contracts have no pause or blacklist controls. Frax's current successor is frxUSD, which has a different Ethereum address and uses custodian contracts and permitted reserve assets for 1:1 minting and redemption. FIP-419's upgrade right is stated for Ethereum FRAX; it does not establish a universal cross-chain conversion right. Holding FRAX does not by itself establish a legal claim on a particular Treasury fund, custodian, yield stream, or project revenue.

Key facts

  • Frax's official historical documentation dates the original launch to December 20, 2020.
  • The canonical Ethereum FRAX contract is 0x853d955aCEf822Db058eb8505911ED77F175b99e and uses 18 decimals.
  • Etherscan reports a live max total supply snapshot of 219,320,045.872600381298337455 FRAX for that Ethereum contract when reviewed.
  • The V1 fractional-algorithmic mint/redeem model is explicitly marked retired in current Frax documentation.
  • FIP-419 introduced frxUSD and specified a 1:1 upgrade path for Ethereum FRAX while keeping legacy Ethereum FRAX functional indefinitely.
  • Current frxUSD is a distinct token: Frax's address documentation lists Ethereum frxUSD at 0xCAcd6fd266aF91b8AeD52aCCc382b4e165586E29.
  • The official legacy-contract documentation says FRAX and FXS contracts have no pause or blacklist controls, but the verified ABI exposes privileged minting, pool, oracle, owner, and timelock functions.
  • The January 2, 2025 frxUSD launch and BUIDL-backed positioning were independently reported by The Block; the PR Newswire item is retained as project-supplied historical evidence, not independent evidence.

Official links

Official websiteWhitepaperBlock explorerX / TwitterGitHub

Categories

StablecoinsUSD StablecoinCrypto-backed StablecoinFiat-backed StablecoinDecentralized Finance (DeFi)Ethereum Ecosystem

Related coins

Tether#3USDC#5USDS#11Dai#20Ethena USDe#24Global Dollar#26

Frequently asked questions

Is FRAX the same token as frxUSD?

No. FRAX is the legacy token and frxUSD is the newer successor with a distinct Ethereum contract address. FIP-419 specifies a 1:1 upgrade path for Ethereum FRAX, but it also says Ethereum FRAX remains functional indefinitely.

Does every FRAX holder have a guaranteed upgrade or redemption right?

No universal right is established. FIP-419 describes a 1:1 upgrade path for Ethereum FRAX specifically; it does not establish a legal claim on reserves or a guaranteed cross-chain conversion for every representation.

What does an FRAX holder legally own or have the right to redeem?

The sources establish an ERC-20 token and a protocol upgrade path, not a legal ownership interest in a Treasury fund or a guaranteed claim on a particular custodian's assets. Do not infer a legal reserve, revenue, or yield right merely from holding FRAX.

Is the original FRAX algorithm still the live Frax product?

No. Frax's V1 documentation labels the original mint/redeem model retired and historical. Current Frax documentation presents frxUSD, a reserve-backed multichain dollar, as the live product.

How much FRAX exists?

Etherscan displayed 219,320,045.872600381298337455 FRAX as the max total supply for the Ethereum contract at review. Supply can change on legacy deployments governed by the contract's mint and burn rules, so this is a dated on-chain snapshot rather than a permanent cap.

Can administrators mint or freeze FRAX?

The verified legacy contract and Frax technical documentation expose owner/governance-controlled minting, pool administration, oracle and timelock setters. The same official documentation says the FRAX and FXS contracts have no pause or blacklist controls. Current owner, governance and timelock addresses should be checked on-chain before relying on that control posture.

External trackers

Choose a tracking site for Legacy Frax Dollar:

Track price on CoinGeckoTrack price on CoinMarketCapTrack price on Binance