At the current supply of GHO, Gauntlet supports 5m USDC, 5m USDT as exogenous assets in the GSM. As GHO supply grows, the debt ceiling for USDT and USDC may need to grow as well, for comparison, DAI PSM capacity is ~15% of total DAI capacity, while minted DAI from PSM is ~17% of total minted DAI.
Gauntlet also recommends price bounds for USDT and USDC at 0.975 in the event of USDT/USDC depeg. Freezing swaps in GSM between GHO and depegged USDC/USDT can prevent the buildup of depegged exogenous assets, thus helping mitigate GHO depeg.
Developing optimal fee strategies is an area that can be further explored. The fee strategy can both incentivize GHO repeg and prevent adversarial GHO depeg. One way is for the fee strategy to depend on GHO price in order to mitigate adversarial actors from causing further GHO depeg. For instance, the sell fee (user swap GHO for USDC in GSM) is 0 if GHO < $1, but the buy fee should be significantly higher.