AIP - 75: Launch stEUR on Gnosis Chain and Arbitrum

Hello,

This is a vote to activate the stEUR contracts on Gnosis Chain and Arbitrum.

Context

The stEUR contract has already been deployed at the same address across different chains. Yet so far, it is only activated on Ethereum mainnet, meaning only stakers of agEUR on Ethereum mainnet can take advantage of the yield that's proposed here.

Having stEUR live on Gnosis Chain and Arbitrum (just like any other L2 or sidechain) means that it'd be possible for agEUR holders there to stake their agEUR and start receiving the savings yield provided by the protocol with limited gas fees.

Proposal

This is a proposal to activate the stEUR contract on Gnosis Chain and Arbitrum, follow the same rate policy as what is currently supported on Ethereum, and generalize this cross chain rate policy and methodology for stEUR for every subsequent deployment of the stEUR contract on another chain.

This means that the stEUR rate should be the same across all chains where it is deployed (starting with Ethereum, Gnosis Chain and Arbitrum here with the proposal) and be computed based on:

• the estimated revenue generated by the protocol across all chains
• the sum of agEUR staked in all stEUR contracts across all chains where stEUR is activated

Intent is NOT to change the rate formula which should remain:

$$rate = \min(0.9\frac{\texttt{est. yearly interest revenue}}{\sum\texttt{agEUR staked}},10%)$$

Implementation

Launching the stEUR contract on a chain only implies:

• granting this contract the minter role on the agEUR contract
• setting the maximum settable rate to 10% so the guardian multisig can update the rates proposed

In this implementation for stEUR cross-chain, this means that to get stEUR on a chain people would need to get agEUR on this chain and then stake it. In particular, stEUR would never be the token that's bridged but rather a token that can be obtained upon staking minted agEUR. Rationale for this is that:

• the protocol already has a functional bridge infrastructure built around agEUR and it'd require significant engineering efforts to make it available to stEUR
• this is purely equivalent to the protocol on a balance sheet level: one agEUR remains a liability to the protocol wherever it is. And an agEUR staked on Ethereum is the same from a protocol perspective as an agEUR staked on Gnosis Chain for instance

Note that the consequence of this is that the value of stEUR is going to value between different chains. 1 stEUR on Gnosis Chain is for instance not the same as 1 stEUR on Ethereum, as the exchange rate between stEUR<->agEUR encoded in each contract implementation is going to vary on each chain.

Value to the protocol

This aims at making stEUR more accessible to smaller DeFi users.

Gnosis Chain is the place where Euro DeFi is growing, and having stEUR there can allow for interesting integrations: like using stEUR as a collateral to borrow EURe and offramp to pay with Gnosis Pay.

When it comes to Arbitrum, the protocol should very soon receive an ARB grant to incentivize stEUR liquidity on the chain. Not only will it make stEUR more accessible, the fact that we can use the grant to incentivize stEUR liquidity means that there is a potential for making Arbitrum the chain with the biggest stEUR adoption

Risks

This increases the risk of creating a huge bridge imbalance between chains, like having negative flows from a chain like Optimism to Gnosis Chain, thus meaning that it'd be impossible for other "organic" users to bridge from Optimism.

It also increases the operational overhead with maintaining and adjusting the rates of the stEUR contract but it's something which can be automated quite easily.

This is why we're proposing here to start with just two sidechains, to potentially later generalize to other chains.

Voting options

1. For, activate Gnosis & Arbitrum
2. Against, do nothing