Utility tokens that convert to FRAX stablecoins at a predefined timestamp.

FXB tokens are simple, trustless tokens that resemble a zero-coupon bond that converts to the FRAX stablecoin on maturity. FXBs are debt tokens denominated in FRAX stablecoins, not a claim on any other asset or collateral. FXB tokens are only convertible to FRAX stablecoins, they do not guarantee FRAX peg, FRAX value, or yield/interest denominated in any other asset except FRAX. FXBs do not entitle the holder to any asset offchain or onchain (other than FRAX stablecoins). Thus, FXBs are not redeemable for US Treasury Bills nor any real-world asset, are not directly backed/collateralized by them (or any specific asset), and do not have any utility except trustlessly converting to FRAX stablecoins at the pre-programmed maturity timestamp generated at their minting. This is important and not merely a semantic distinction because it directly defines the normative and economic property of FXBs. Frax Bond tokens only guarantee that they convert to FRAX on a one-to-one basis through smart contracts that issue them.

While 1 FXB will always equal 1 FRAX, the FXB AMO auctions off FXBs at a discount to face value. This discount provides the equivalent of RWA yield to buyers without the assumption of RWA risk.

FXBs allow the formation of a yield curve to price the time value of lending FRAX back to the protocol itself. Each FXB token is a fungible ERC20 token deployed from an onchain factory contract. Immediately at minting time, FRAX stablecoins are minted into the FXB redemption contract for conversion on maturity. This prevents any external actions being necessary for the full FXB cycle to occur and entirely remains trustless. There can be multiple FXB series circulating at all times (decided by frxGov) and no limit for the minimum or maximum maturity timestamp for FXBs deployed from the factory.

FXBs mature at the end of the day of their maturity date in UTC and have no expiration. For example, the MAR-31-2024 FXB is able to be burned back for its' corresponding FRAX as soon as 1711929600.

Series Auctions

FXB series price discovery happens through a continuous gradual Dutch auction (GDA) auction system that has quantity and price limit set by frxGov. This guarantees that FXB tokens are not sold for prices lower than the floor limit. Auctions happen through the FXB AMO contract and are trustless, permissionless, and non-custodial. New auctions can happen at any time through frxGov and FXB AMO Timelock initiated transactions.


FXB Factory (permissioned): 0x7a07D606c87b7251c2953A30Fa445d8c5F856C7A

Auction factory (permission-less): 0x983aF86c94Fe3963989c22CeeEb6eA8Eac32D263

FXB AMO: 0x452420df4AC1e3db5429b5FD629f3047482C543C

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