Proposal to add Euro Pool (cEUR/agEUR/EUROC) to the Gauge Controller


The Celo community, in partnership with Angle Protocol, is proposing to add the Euro Pool (cEUR/agEUR/EUROC) to the gauge controller so users can assign gauge weights and receive CRV rewards. This way, cEUR, the euro-tracking stable asset on Celo can partner with and add value to the Curve community.

References/Useful links:


Reserve stats:

Stability mechanism:


Celo Whitepaper & Stability Protocol:

Source code:

Protocol Description:

cEUR is one of Mento Protocol’s on-chain collateralized stable assets on the Celo blockchain. Mento stable assets are backed by an on-chain Reserve, which includes a diversified portfolio of assets that supports the ability of the Mento Protocol to expand and contract the supply of Mento stable assets in line with user demand. The Reserve is currently overcollateralized by 260% and consists of over $220M in holdings made up by 110M CELO, 881.9 BTC, 10.3K ETH, 44M DAI, 42.9M USDC, and 83.3K cMCO2, against an outstanding supply of $91M in stable assets. BTC, ETH, DAI, and USDC (before accounting for CELO) in the Reserve account for greater value than the outstanding supply of Mento stable assets.

When the price of cEUR is below €1, an arbitrager can burn 1 cEUR and receive €1 worth of CELO from the reserve. When the price of cEUR is above €1, the arbitrager can mint 1 cEUR by depositing €1 worth of CELO to the Reserve. The Reserve is then periodically rebalanced to maintain the target allocation of reserve assets as per Celo governance.

The cEUR has been bridged over using Wormhole. The token address on Ethereum is 0xEE586e7Eaad39207F0549BC65f19e336942C992f.

The Reserve:

CELO is held in the Reserve smart contract. The remaining non-CELO assets in the Reserve are managed through a governance elected reserve entity that can draw up to 5% from the reserve smart contract a day for rebalancing. The entity uses qualified and licensed custodians, currently Anchorage (Anchorage | Celo) and Hex Trust (, which do not operate in countries that are blacklisted by the Financial Action Task Force (FATF) or subject to any sanctions prohibitions. Custodians are required to make publicly available the assets they hold on behalf of the Reserve to ensure that Celo stakeholders and the broader Celo community have full transparency with respect to Reserve assets.

Celo Reserve


Celo with Custodian













Anchorage holdings report (Anchorage | Celo)

Hex Trust and Celo (Hex Trust Partners with Celo, Bringing Institutional Access to the Mission-Driven Ecosystem | Hex Trust)


Following the proposal to deploy Curve on Celo, a cEUR pool is a complementary step towards further integrating the Celo protocol with the wider ecosystem. A gauge will allow the Celo ecosystem to begin incentivizing a cEUR pool. This will build on Celo’s recent partnership with Wormhole to bridge cEUR and an upcoming deployment of Curve on the Celo blockchain.

Adding a gauge on Curve will help increase liquidity of cEUR, and help increase the Celo ecosystem’s efforts to help build real world use cases and unlock the potential of regenerative finance. Since Curve has the largest liquidity for stable assets and given Celo’s partnership with Wormhole, the Celo community would like to make it easier for Ethereum DeFi users to participate in the Celo Ecosystem and earn rewards on Curve for cEUR.

Additionally, a gauge on Curve will help liquidity to enable volume in the cEUR/agEUR/EUROC. For instance, users will be able to access the Celo ecosystem on Ethereum and also exit the Celo ecosystem to participate in DeFi projects or engage with products with Angle Protocol through the Euro Pool on Curve. Users can also utilize EUROC as an on/off-ramp to transition assets between Angle Protocol and the Celo ecosystem.

More on cEUR

As part of their research, the Mento team has simulated various market conditions (summary article), including bear market conditions. And while simulations can never capture all the complexities of the real world, analyses showed stability through a wide range of adversarial conditions and informed crucial design choices, which were presented and approved through the governance process, such as diversifying the Reserve by including low-volatility assets.

In light of recent market volatility, the Celo community has reacted quickly to market conditions to further the collateralization behind Mento stable assets. In May, the Celo community approved CGP#56 to increase the amount of DAI in the reserve from 5% to 29.5% with 99.8% voting in favor. In June, the community decided with #CGP62 to double down on the collateralization and to introduce a 1:1 backing of Mento stable assets through a mix of DAI and USDC, in addition to all remaining assets in the Reserve.

Why agEUR?

agEUR is Angle Protocol’s Euro stable asset. While it’s not the biggest stableasset in market cap, it is the most liquid and integrated Euro stable asset in the DeFi ecosystem. Not only does it have several gauges on Curve, but it’s also available across different lending protocols like Aave or Euler. In addition, it can be exchanged at a 1:1 rate for other USD stable assets and wETH. Arbitrages with these assets is what allows the pools where agEUR is involved to consistently have significant volumes.

The agEUR relies on an over-collateralized model (190% collateral ratio so far), and has consistently held its peg since its launch in November 2021. In the past, it has also helped other Euro stablecoins (like EURs) maintain peg when the redemption mechanism failed to work well.

The different versions and modules of the protocol have been audited multiple times, and the protocol has received one of the highest grades from DeFi Safety in terms of transparency.


While there are other fiat-backed Euro-denominated stablecoins in circulation, we ultimately chose EUROC for this Euro Pool for the following reasons:

  1. Circle’s market significance - Circle’s flagship USD-denominated stable asset, USDC, is the 2nd largest stable asset by market cap with more than $55B in circulation. USDC utilizes a full-reserve model, where it is redeemable 1:1. In recent market volatility, USDC has not only remained stable but has grown significantly in market share. We expect EUROC to become a fiat-backed Euro stable asset as it already has a large captive audience with USDC, implements a similar full-reserve model that is stable and redeemable 1:1, and addresses a significant market need for a reliable fiat-backed Euro stable asset. As stable assets become increasingly regulated, Circle’s legal status and reputation should be an asset.

  2. Low market cap of other fiat-backed Euro stable assets - EURt (Tether Euro) currently has a market cap of $41M while EURs (Statis Euro) has a market cap of $127M. (Source: STASIS EURO price today, EURS to USD live, marketcap and chart | CoinMarketCap & Tether EURt price today, EURT to USD live, marketcap and chart | CoinMarketCap). Together, both EURt and EURs represent less than 0.15% of the current global stable asset market.

  3. Strategic alignment with The Celo Reserve - Roughly 20% of The Reserve is currently composed of USDC. Most recently, the implemented governance proposal incorporated a 1:1 backing mechanism of Mento stable assets. The Reserve may expand to include EUROC as demand for multi-currency Mento stable assets grows, which may inherently create more systemic demand for EUROC on the Mento protocol on the Celo blockchain as The Reserve expands to support the supply of Mento stable assets with fiat-backed assets.



Celo uses a formal on-chain governance mechanism to manage and upgrade the protocol such as for upgrading smart contracts, adding new stable assets, or modifying the Reserve’s target asset allocation. All changes must be voted on by CELO holders. A quorum threshold model is used to determine the number of votes needed for a proposal to pass.

More details can be found here


The Mento Protocol relies on oracles that report the CELO/EUR trading price exchanges, including the below:

  • Bittrex

  • Coinbase

  • Binance

More details regarding the oracles and stability mechanism can be found here and here


Celo Protocol has been audited by OpenZeppelin, Certora, Teserakt, and Trailofbits.

The process of reserve trading has been internally and externally (NCC group) audited.

The stability protocol analysis was performed by Gauntlet and Economic Analysis by Prysm Group.

Audits can be found here

Centralization vectors:

As a threshold matter, the Mento Protocol is a stable asset platform that runs on the Celo Layer-1 decentralized, permissionless blockchain.

  1. Portions of the Reserve are held in centralized custody via Anchorage and Hex Trust. There is a multisig that can access these funds. The identity of these individuals and the number of trustees and thresholds for the multisig are not disclosed for security reasons. However, as mentioned above, custodians are required to make publicly available information on the assets they hold on behalf of the Reserve to ensure that Celo stakeholders and the broader Celo community have full transparency with respect to reserve assets. The reserve assets can be viewed on-chain at all times at the addresses listed above.

  2. Oracles that the Mento stability mechanism relies on are currently run through on-chain smart contracts only accessible to certain accounts maintained by cLabs, with the ability for additional access to be added through the protocol’s on-chain governance process. A decentralization plan for the oracle infrastructure is currently in discussion. The Mento stability mechanism has safeguards in place to ensure that the reserve is protected in the case of oracle failure. (Celo Stability Algorithm (Mento) | Celo Documentation)

  3. Presently, there is an absence in the general market of a reliable and market-tested cross-chain value transfer solution. As such, the ‘cross-chain’ rebalancing still requires assets (e.g. Celo) be transferred via multisig to a CEX, traded against other assets (e.g. BTC) and then transferred back to a reserve address. Although the reserve address may be on a different blockchain, the whole process is fully transparent because the movement of funds in and out occurs on-chain and allows for the calculation of the implicit exchange rate. The administrative action to accomplish this change is required due to the currently available market infrastructures and is not specific to Celo. Before a trading session is started, a review is completed to check whether the distance to target weights and current liquidity levels require running a session—if not, no trading occurs. If yes, assets are traded as described above. The whole process of reserve trading has been internally and externally (NCC group) audited.

Market History:

According to CoinMarketCap, since 29 June 2021 and until 4 July 2022, on a closing basis, cEUR was within +/-1.25% of the peg, 95% of the time and within +/-2.25% 99.7% of the time. cEUR withstood the market pressure caused by the collapse of UST; the on-chain stability mechanism Mento protocol immediately responded to excess supply around May 11, and remains within the peg as of the date of this proposal. Deviations from the peg are observed in relatively illiquid venues where small transaction sizes have a disproportionate impact on the price.


Pablo from Angle Protocol here! Obviously, super in favor of this proposal, great to bring new Euro stablecoins like cEUR to Curve!