Crypto Gloss

Frax Finance

Frax Finance began in 2020 as an experiment: could a partially-collateralized stablecoin maintain a $1 peg more efficiently than fully-collateralized designs? For nearly two years it worked — FRAX maintained its peg using a combination of USDC reserves and algorithmically minted FXS. Then the Terra/LUNA collapse of May 2022 changed everything. Although Frax’s mechanism was categorically different from UST’s (Frax had real USDC reserves; UST had only LUNA), the market’s trust in any algorithmic element disappeared. Frax’s founder Sam Kazemian responded by systematically moving to full collateralization — and pivoting Frax from a single stablecoin to an entire DeFi ecosystem: a liquid staking protocol, a Layer 2 blockchain (Fraxtal), and an ambitious concept called the Frax Price Index (FPI) for a “CPI-pegged” universal stablecoin.

Background: The Fractional-Algorithmic Concept

Frax launched October 2020 as the first “fractional-algorithmic” stablecoin — a middle path between fully collateralized (USDC: $1 in reserves per $1 USDT) and purely algorithmic (UST: zero real reserves).

Original FRAX mechanism:

  • Every FRAX has partial USDC backing + partial FXS burned as “algorithmic backing”
  • Collateral ratio (CR) started at 100% and was adjusted by market demand
  • If FRAX demand was high → CR dropped (less USDC needed, more algorithmic)
  • If FRAX depegged → CR rose (more USDC reserves added)

Example at 85% CR:

  • To mint 1 FRAX: deposit $0.85 USDC + burn $0.15 FXS
  • To redeem 1 FRAX: receive $0.85 USDC + $0.15 FXS (newly minted)

Why it worked initially: FRAX maintained its peg through the 2020–2022 bull market, validating that partial reserves + market confidence could maintain stability. FRAX grew to $3 billion in circulation.

FRAX v3: Full Collateralization

After the Terra collapse (May 2022), Frax systematically raised its collateral ratio:

Timeline:

  • May 2022: CR was ~83%; post-Terra governance pushed toward 100%
  • January 2023: Governance passed FIP-188 (“Frax v3”) — target CR = 100%
  • 2023–2024: Revenue used to accumulate additional reserves until CR reached 100%

What backs FRAX v3:

  • USDC (primary)
  • Ethereum staking yield (frxETH/sfrxETH)
  • Curve/Convex LP positions
  • FraxBond (FXBS) — lending protocol revenue
  • Approved RWA (Real World Assets) via partnerships (Ondo Finance, by BlackRock for US treasuries)

Current FRAX: Essentially a yield-bearing algorithmic stablecoin that is 100%+ backed — more similar to DAI than to its original design. The “algorithmic” element is effectively removed; FRAX is now more credible but less capital-efficient.

frxETH and sfrxETH: Liquid Staking

Frax’s most successful expansion — a dual-token liquid staking system launched October 2022:

frxETH (Frax Ether):

  • ERC-20 token; 1:1 peg to ETH
  • Deposit ETH → receive frxETH
  • frxETH itself does NOT automatically earn staking rewards (unlike stETH)
  • Instead, frxETH maintains a stable peg for use as Curve LP collateral

sfrxETH (Staked Frax Ether):

  • Yield-bearing wrapper for frxETH
  • Deposit frxETH → receive sfrxETH
  • sfrxETH accrues all ETH staking rewards from ALL frxETH validators
  • Only sfrxETH holders earn yield; frxETH holders don’t (but frxETH/ETH Curve LPs earn other rewards)

Why this design is clever:

  • Most liquid stakers hold sfrxETH to earn yield
  • Some hold frxETH in Curve pools (earning Curve/Convex rewards instead of staking yields)
  • ALL staking rewards concentrate on sfrxETH holders → sfrxETH yield > typical LST yield
  • Historically: frxETH/sfrxETH offered 5–7% APY vs. Lido stETH’s 3.5–4%

Frax validator set: Frax runs its own validators using user-deposited ETH; more centralized than Rocket Pool (permissioned operator set) but fewer assumptions than custodied exchange staking.

Fraxtal: The L2 Blockchain

In 2024, Frax launched Fraxtal — an Ethereum Layer 2 built on the OP Stack (same stack as Base, Optimism):

  • Native yield: ETH and FRAX bridged to Fraxtal automatically earn yield (sfrxETH staking rewards, FRAX interest)
  • Flox points: Activity on Fraxtal earns “FLOX” points for gas rebates and eventual governance
  • EVM compatible: All Ethereum tooling works; DeFi protocols deployable without modification
  • Gas token: ETH; frxETH earns yield regardless
  • FraxSwap: Frax’s native AMM with TWAMM (Time-Weighted Average Market Maker) for large order execution

Protocol Governance and Revenue

FXS (Frax Shares) token:

  • Governance: FXS holders vote on collateral ratio, protocol parameters, fee settings
  • Revenue accrual: Protocol revenue (staking validator revenue, AMM fees, FRAX lending interest) used for FXS buybacks
  • veFXS: Lock FXS for voting rights and yield boosts (similar to veCRV); locked FXS = veFXS for 1 week to 4 years

Protocol revenue sources:

  1. Ethereum validator tips + MEV on ~50,000+ ETH in validators
  2. Frax lending (FRAX borrowed at interest-bearing rates)
  3. AMM fees on FraxSwap
  4. Interest on RWA holdings

FXS buyback mechanic: Revenue → buy FXS from open market → reduces circulating supply → accretive to remaining holders

Curve Integration and the “Frax Wars”

Frax has historically been the most aggressive protocol in Curve Wars:

  • Massive veCRV position (via direct locks and Convex)
  • FRAX/USDC Curve pool has been one of the deepest stablecoin pools
  • frxETH/ETH pool: Frax offered high Frax rewards to incentivize frxETH adoption, making it temporarily more attractive than stETH/ETH Curve pools
  • FraxBP (Frax Base Pool): A FRAX/USDC liquidity pool replacing the traditional 3pool as base pair for many Curve pools — Frax’s attempt to become Curve’s foundational liquidity layer

Frax Price Index (FPI)

Frax’s most ambitious concept: a stablecoin pegged not to $1 but to a US CPI basket.

  • FPI token: Pegged to US CPI reading; if inflation is 5%/year, FPI’s redemption value increases 5%/year
  • Goal: A stablecoin that maintains real purchasing power, not nominal dollar value
  • FPIS: Governance token for FPI protocol
  • Status: Launched but small; requires reliable CPI oracle (Chainlink used) and deep protocol revenue to fund the inflation peg

Social Media Sentiment

Frax’s reputation significantly improved post-Terra by demonstrating crisis management — moving to full collateralization while maintaining operations showed institutional-level seriousness. Sam Kazemian is well-regarded as a principled founder who listened to governance and adapted the protocol’s design in response to evidence. The frxETH/sfrxETH design is widely praised as clever — concentrating validator yield into sfrxETH while using frxETH for LP is a genuinely novel liquidity engineering approach. Fraxtal as an L2 is seen as ambitious but the OP Stack competition is very crowded. FXS has underperformed relative to competitor governance tokens (CRV, AAVE) in some bull markets — buyback mechanism is good but ecosystem mindshare lags. The FPI concept is respected intellectually but has struggled to achieve meaningful adoption — most stablecoin users prefer the simplicity of dollar pegs.

Last updated: 2026-04

How to Use FRAX and frxETH

Buy FXS on major exchanges including

Store FXS securely:

To stake ETH via Frax: frax.finance → deposit ETH → receive frxETH → stake for sfrxETH

Related Terms

Sources

Kazemian, S., Nguyen, T., & Mooser, J. (2021). Frax: Fractional-Algorithmic Stablecoin Protocol. Frax Finance Whitepaper v2.

Kozhan, R., & Viswanath-Natraj, G. (2021). Decentralized Stablecoins and Collateral Risk. Working Paper, Warwick Business School.

Evans, A. (2021). Liquidity Provider Returns in Geometric Mean Markets. arXiv:2006.08205.

Berentsen, A., & Schär, F. (2021). A Short Introduction to the World of Cryptocurrencies. Federal Reserve Bank of St. Louis Review, 101(1).

Werner, S.M., Perez, D., Gudgeon, L., Klages-Mundt, A., Harz, D., & Knottenbelt, W.J. (2022). SoK: Decentralized Finance (DeFi). Financial Cryptography 2022.