General minimum-deposit policy for high-usage stablecoins and native tokens

[d10r]

Stablecoins play an important role for payment protocols like Superfluid and should thus get elevated attention.
Currently, USDCx on Polygon and USDCx on Optimism make up the bulk of Superfluid streams.

In order to ensure robustness of the solvency system, we should introduce a minimum deposit for such streams.

Superfluid first deployed on Polygon (then Matic) and Gnosis Chain (then xdai chain), when transaction fees on both this chain were very low and liquidation costs weren't an issue.
On Polygon, this has changed in the meantime. Also, deployments on significantly more expensive chains (Optimism and Arbitrum) were made. This has led to a situation where Sentinel operators, which are at the core of the solvency system, run the risk of operating at a loss if indiscriminately liquidating all critical streams.

I propose to set minimum deposits for stablecoins once there are 1000 or more active streams open in that SuperToken.
As values for the minimum deposit I propose:

• Polygon: 0.2 $
• Optimism: 0.5 $
• Arbitrum: 0.5 $

As suggested by @ngmachado I also propose to set a minimum deposit for the native coin wrapper SuperToken to this values:

• Polygon: 0.1 MATIC
• Optimism: 0,0002 ETH
• Arbitrum: 0,0002 ETH

The reason why native coin deposits are lower is that blockspace demand and thus gas price tend to somewhat correlate with the native token price, thus less margin is needed. This is also reflected in minimum deposit values set on Ethereum Mainnet.

This proposed values aren't at this time derived from a well defined risk model, but based on observations about transaction costs and their volatility over an extended period of time. They also have a margin for potential future increases in overall gas prices on those chains.

[ngmachado]

I agreed with your proposal and find that your observations about the costs are in line with my own.

In addition, I would suggest extending the proposed minimum deposit requirements to not only include stablecoins such as USDCx, but also the native coins of each chain such as MATICx and ETHx.

However, it is important to note that a formalized process and a well-defined workflow and risk model would need to be developed to ensure that decisions regarding minimum deposit requirements are based on sound analysis and consideration of all relevant factors.

It is worth noting that this is an ongoing process and that the proposed minimum deposit requirements on Superfluid should be periodically revisited to ensure that they remain appropriate and effective.

[d10r]

proposal updated with this suggestion included

[seliqui]

Would suggest to setting the minimum deposit at a value that makes closing them still makes them profitable + some buffer for price hikes and to balance out negative spending for previous and exisiting streams that already run with a lower deposit.

As for USDCx on Optimism, setting 0.5 is already within that margin.