Fei Protocol
Protocol changes since the white paper release

FIP-31: Upgrade Governance Timelock - Oct 7, 2021

Upgrades the FEI DAO Timelock and grants the Guardian the power to veto proposals.
Proposal 21852815661133861431069342628197440301017315762387828688826283933340724199435 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-32: Pre-V2 Contract Upgrades - Oct 7, 2021

Upgrades a few PCV contracts to be compatible with the V2 Collateralization Ratio:
  1. 1.
    ETH UniswapPCVDeposit
  2. 2.
    DPI UniswapPCVDeposit
  3. 3.
    ETH bonding curve
  4. 4.
    Ratio PCV controller
This proposal also removes reweights, making the v2 stability mechanism of 1:1 redemption the primary one.
Proposal 93357291593194312261346499544567298679261704308288227159285002033190414845299 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-30: Upgrade to OZ Governor - Oct 3, 2021

Upgrade DAO to OZ Governor Reduce voting delay from 3333 blocks to 1 block Increase voting period from 10000 blocks to 13000 (~48h)
Proposal 23 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-28/29: FeiRari TRIBE and Optimistic Approval - Sept 26, 2021

  1. 1.
    gives the OA timelock admin control of all FeiRari components and parameters
  2. 2.
    gives OA timelock admin of TribalChief and revokes old timelock
  3. 3.
    blocks TRIBE borrowing from the pool in anticipation of single-sided TRIBE staking rewards
  4. 4.
    mints 50M FEI to the OA timelock for future lending deployments
  5. 5.
    mints 1M FEI to seed Fuse pool 22 (BadgerDAO)
Proposal 22 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-26/27: Bonding Curve Cap and Spread Updates - Sept 23, 2021

This proposal introduces a number of changes related to the FEI redemption spread and bonding curve parameters.
Tightening FEI redemption spread to 0.5%:
  1. 1.
    Set Bonding Curve Buffer to 0.5% (from 1%)
  2. 2.
    Set Reserve Stabilzier price to $0.995 (from $0.99)
Increasing Bonding Curve capacity:
  1. 1.
    Set DAI Mint Cap to 150M (from 50M)
  2. 2.
    Set DAI Scale to 100M (from 50M)
  3. 3.
    Set DAI Pre-Scale Discount to 0
  4. 4.
    Set DPI Mint Cap to 50M (from 10M)
  5. 5.
    Set RAI Mint Cap to 20M (from 10M)
Proposal 21 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-22: Deploy FEI liquidity and TRIBE incentives to Aave - Sept 21, 2021

Add 4M TRIBE of incentives to Aave for borrowing FEI and deposits 25M minted FEI
Proposal 20 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-24: Gas Refund for TribalChief Transition - Sept 15, 2021

Grant a 400 FEI gas refund to all users who transitioned from the old staking system to the new one
Proposal 19 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-15: TribalChief + Optimistic Approval - Sept 5, 2021

Upgrade Fei’s staking infrastructure to the TribalChief. The TribalChief allows TRIBE emissions to be split among a configurable set of staking reward tokens in different proportions. It also allows for reward multiplier boosts for locking the stake to be added on a per-pool basis.
It will start the emissions at 75 TRIBE per block, roughly equal to the current emissions with the intention of following the 2 year decreasing schedule with regular emission rate decreases.
The pool will start with two incentivized pools at equal (1000 AP) proportions:
  • FEI-TRIBE Uniswap V2 LP
  • FEI-3Crv Curve Factory Metapool LP
The proposal also introduces Optimistic Approval, which is a multisig gated by a Timelock that can be vetoed by the DAO or the Guardian. All TribalChief actions can be taken by Optimistic Approval other than increasing emissions and withdrawing TRIBE. These actions can only be performed by the DAO.
Proposal 18 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-23: Raise Reserve Stabilizer Floor - Aug 29, 2021

Raise reserve stabilizer price from $.95 to $.99 worth of ETH. Users can now redeem FEI for $1 plus a 1% fee.
Proposal 17 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-20: Deploy Dripper ETH - Aug 29, 2021

Allocate the ~164k ETH in the EthPCVDripper to productive deployments
  • 75k to Compound
  • 75k to Aave
  • 14k to Lido stETH
Proposal 17 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-19: RAI Bonding Curve - Aug 25, 2021

Deploy a RAI-specific bonding curve allowing the purchase of FEI with RAI.
This proposal has the following parameters:
  • Scale: 6M FEI
  • MintCap: 10M FEI
  • Pre-scale discount: 0.3%
  • Post-scale premium: 2%
  • Oracle: Composite Chainlink RAI-USD (2% deviation threshold RAI-ETH and 0.5% ETH-USD)
  • Keeper incentive amount: 100 FEI
  • Keeper incentive frequency: 604800s (1 week)
The RAI PCV raised will go 50% to Aave and 50% to Fuse Pool 9.
Proposal 15 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-13b: FEI Lending Deployments - Aug 22, 2021

Deploy FEI liquidity to the following pools to bootstrap lending markets:
Fuse Pool 9 (Reflexer + Frax) - 1M Fuse Pool 25 (BarnBridge) - 1M Fuse Pool 26 (Tokemak) - 1M Fuse Pool 27 (StakeDAO) - 1M
Proposal 14 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-10a: Add a DAI Bonding Curve - Aug 19, 2021

Deploy a DAI-specific bonding curve allowing the purchase of FEI with DAI.
This proposal has the following parameters:
  • Scale: 50M FEI
  • MintCap: 50M FEI
  • Pre-scale discount: 0.3%
  • Post-scale premium: 2%
  • Oracle: Chainlink DAI-USD (2% deviation threshold)
  • Keeper incentive amount: 100 FEI
  • Keeper incentive frequency: 604800s (1 week)
The DAI PCV raised will go 100% to Compound.
Proposal 13 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-14: Add DPI Bonding Curve - Aug 9, 2021

Deploy a DPI-specific bonding curve allowing the purchase of FEI with DPI. New bonding curves offer FEI at a discount relative to the oracle price before the scale target is reached. Beyond scale, there is a premium associated with purchasing, with an additional minting cap.
This proposal has the following parameters:
  • Scale: 10M FEI
  • MintCap: 10M FEI
  • Pre-scale discount: 1%
  • Post-scale premium: 2%
  • Oracle: Chainlink DPI-USD (2% deviation threshold)
  • Keeper incentive amount: 100 FEI
  • Keeper incentive frequency: 604800s (1 week)
The DPI PCV raised will be split 90% between a SushiSwap DPI-FEI pool and 10% to the Index Coop Fuse Pool.
Proposal 11 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance
Included a second proposal to OTC for 100,000 INDEX tokens in exchange for:
  • 633.15 ETH from the dripper
  • 991512.9 FEI minted
  • 1235325.922 TRIBE from the DAO Treasury
These are delegated to Matthew Graham who will vote on behalf of TRIBE holders pending snapshot votes.
Proposal 12 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-13: FEI Lending Deployments - Aug 3, 2021

Deploy FEI liquidity to the following pools to bootstrap lending markets:
C.R.E.A.M - 5M Kashi FEI (asset) / TRIBE (collateral) - 2.5M Kashi FEI (asset) / ETH (collateral) - 2.5M Kashi FEI (asset) / xSushi (collateral) - 2.5M Kashi FEI (asset) / DPI (collateral) - 1M Fuse Pool 6 (Tetranode’s Locker) - 1M Fuse Pool 7 (CLG + Tetranode UpOnly) - 1M Fuse Pool 3,3 (Olympus Pool Party) - 1.333M Fuse Pool 19 (Index Coop) - 1M Fuse Pool 24 (Harvest Finance) - 1M
Proposal 10 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-11: Re-parameterize FeiRari

Update existing FeiRari Fuse Pool Parameters:
  1. 1.
    Reduce Close Factor from 50% to 33%
  2. 2.
    Reduce Liquidation Incentives from 10% to 8%
  3. 3.
    Increase FEI, ETH and DAI collateral ratio from 75% to 80%
  4. 4.
    Update to FEI IRM
    1. 1.
      Reduce FEI Base Rate from 2.73% to 0%
    2. 2.
      Reduce FEI Initial Slope Multiplier from 36.40% to 7%
    3. 3.
      Reduce FEI Second Slope Multiplier from 1650% to 400%
  5. 5.
    Update to TRIBE IRM
    1. 1.
      Reduce TRIBE Base Rate from 2.73% to 0%
    2. 2.
      Reduce TRIBE Initial Slope Multiplier from 53.75% to 20%
    3. 3.
      Reduce TRIBE Second Slope Multiplier from 4000% to 400%
  6. 6.
    Update to DAI IRM
    1. 1.
      Reduce DAI Base Rate from 2.73% to 0%
    2. 2.
      Reduce DAI Initial Slope Multiplier from 53.75% to 10%
    3. 3.
      Reduce DAI Second Slope Multiplier from 4000% to 400%
  7. 7.
    Update to ETH IRM
    1. 1.
      Reduce ETH Base Rate from 2.73% to 0%
    2. 2.
      Reduce ETH Initial Slope Multiplier from 53.75% to 8%
    3. 3.
      Reduce ETH Second Slope Multiplier from 4000% to 400%
Proposal 9 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-12: Incentivize Saddle D4 - July 10, 2021

Allocate 2M TRIBE from the DAO Treasury towards liquidity incentives for Saddle's D4 pool https://saddle.exchange/#/pools/d4/deposit
Proposal 8 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-9: Staking ETH on Lido - July 3, 2021

Stakes 10,000 ETH from PCV into stETH via Lido
Proposal 7 for Eip155:1:0x0bef27feb58e857046d630b2c03dfb7bae567494 governance

FIP-4: Remove Direct Incentives - June 20, 2021

By snapshot vote, the community has decided to remove direct incentives from the Fei Protocol functionality as mentioned in the original white paper.
The UniswapIncentive contract is no longer in use (previously at https://etherscan.io/address/0xfe5b6c2a87A976dCe20130c423C679f4d6044cD7)
Snapshot for FIP-4

FIP-8: Use Chainlink Oracle - June 18, 2021

Upgrades the oracles throughout Fei Protocol to use the Chainlink ETH-USD oracle wrapper instead of the UniswapOracle

FIP-3: Regular Reweights - May 23, 2021

FIP-3 reinstates reweights on the FEI-ETH Uniswap pair with a fixed cadence. This removes the "incentive parity" trigger condition for reweights on the EthUniswapPCVController.
Included parameter changes:
  • Set reweight frequency to 4 hours
  • Lower the min distance below peg for a reweight from 1% to 0.5%
  • Lower reweight keeper reward to 200 FEI
The code for these changes can be found here: https://github.com/fei-protocol/fei-protocol-core/pull/96

FIP-5: Bonding Curve Allocation Update - May 18, 2021

FIP-5 updates the bonding curve allocation to send funds to the EthReserveStabilizer via the EthPCVDripper instead of to the EthUniswapPCVDeposit as before.
It also includes an update to the EthUniswapPCVDeposit where deposits can only occur when the FEI-ETH spot price is within 1% of the oracle price.
An adapter contract that allows ETH transfers to conform to the IPCVDeposit interface.
A PCV controller that allows for withdrawals of a percentage rather than a raw amount of PCV. This is useful for contracts like the EthUniswapPCVDeposit where the ETH amount held varies based on market conditions.
The code for these changes can be found here: https://github.com/fei-protocol/fei-protocol-core/pull/98

FIP-2: FEI Redemption and TRIBE Staking Rewards - April 29, 2021

FIP-2 allows FEI redemption at $0.95 and doubles the FEI-TRIBE LP staking rewards
Responsible for exchanging FEI for ETH at $0.95 relative to the UniswapOracle price. Has the Burner🔥role so that approval is not needed to interact with it. Receives ETH in 5k batches from the EthPCVDripper every hour.


Drips ETH to the EthReserveStabilizer in 5k increments every hour. The dripper prevents the EthReserveStabilizer from holding more than 10k ETH allowing a smoother and safer release of potentially large amounts of ETH to target contracts.
The drip can be called by any address and is not incentivized directly with FEI
300k ETH are sent to the EthPCVDripper from the EthUniswapPCVDeposit


When the FeiRewardsDistributor receives new TRIBE, it allocates an amount proportional to all prior drips to the very first drip, frontloading the distribution. If the 100 million TRIBE are sent directly to the distributor then the following week would have 6x rewards (1x base rewards + 100% boost x 5 drips).
To smoothen out the front-loading, the TribeDripper sends the 100 million TRIBE to the FeiRewardsDistributor over 3 weeks using 47m, 31m, and 22m TRIBE respectively.
Week 1: 1x base rewards + 47% boost x 5 drips = ~3.35x Week 2: 1.47x base rewards + 31% x 6 drips = ~3.33x Week 3: 1.78x base rewards + 22% x 7 drips = ~3.32x Week 4+: 2x base rewards
The TribeDripper is at https://etherscan.io/address/0x65b3Ea26c492de0c2f2D8Abe84eB831796d6eDb1 with an unincentivized function drip() that can be called weekly for 3 drips

Pre-Launch - Feb 2021


The Guardian maintains the ability to revoke roles, and pause certain contracts and methods. It can also force reweights.


The white paper specification for the Genesis Group doesn’t address the unintended effect that the average price paid is always lower than the "next price" which is the price that is listed on Uniswap. This creates a perverse incentive to participate in the Genesis Group to arbitrage the group. To solve this we have implemented "thawing" where the list price of FEI/ETH starts at the average genesis price and thaws up to the target peg over 2 weeks.


In the white paper, bonding curve purchases of FEI directly fund (ETH) the PCV. Thanks to a recommendation from Ashwin Ramachandran, we are splitting this allocation to Uniswap into a separate flow available for keepers. This lowers bonding curve purchases to around 100k gas, a 66% reduction, making it cheaper than most Uniswap purchases! These batched transactions are always available and incentivized once a day for 500 FEI.

Reweight Reward

PCV reweights receive a flat reward in FEI rather than the percentage approach mentioned in the white paper.

Escape Genesis

In the unlikely event that the GenesisGroup launch function is frozen in a bad state, we’ve added a way to exit back into ETH. This opens 3 days post Genesis.

Pre-Swap TRIBE

To mitigate frontrunning of TRIBE in the DEX offering, we allow users to pre-swap a portion of their Genesis Group FEI stake to buy TRIBE. This gives users the ability to participate in the very first TRIBE purchase at the best IDO price.

IDO Normalization

Given that the pre-swap creates a large slippage and back-running opportunity, a trader could arbitrage the group by joining Genesis and pre-swapping 100% of the FEI for TRIBE with the intention of immediately selling back out.
We now normalize the IDO price to what the Genesis Group pays including slippage by burning directly from the pool to prevent this backrunning opportunity.

Bonding Curve Shift

In the white paper, the bonding curve starts at a 0 price and approaches the peg at the scale target. To achieve lower undercollateralization in the PCV, we’ve added a “k” shift to initiate the bonding curve higher up at an elevated starting price.

Sell Disincentive (Burn) Calculation

The current implementation integrates the burn function from the white paper with respect to the distance from the peg.


A custom Uniswap router that allows the user to bound their buy rewards or sell penalties when trading on the incentivized uniswap pool.

White paper - Jan 11, 2021

Last modified 3mo ago