Adjust EarnerRateModel to be less conservative

script/DeployEarnerRateModel.s.sol

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: UNLICENSED
+
+pragma solidity 0.8.23;
+
+import { Script, console2 } from "../lib/forge-std/src/Script.sol";
+import { EarnerRateModel } from "../src/rateModels/EarnerRateModel.sol";
+
+contract DeployEarnerRateModel is Script {
+    // NOTE: Ensure this is the correct MinterGateway testnet/mainnet address.
+    address internal constant _MINTER_GATEWAY = 0xf7f9638cb444D65e5A40bF5ff98ebE4ff319F04E; //mainnet
+    // address internal constant _MINTER_GATEWAY = 0x4eDfcfB5F9e55962EF1A2eEf0b56A8FaDbaBA289; // sepolia
+
+    function run() external {
+        address deployer_ = vm.rememberKey(vm.envUint("PRIVATE_KEY"));
+
+        console2.log("Deployer:", deployer_);
+
+        vm.startBroadcast(deployer_);
+
+        address earnerRateModel_ = address(new EarnerRateModel(_MINTER_GATEWAY));
+
+        vm.stopBroadcast();
+
+        console2.log("Earner Rate Model address:", earnerRateModel_);
+    }
+}

src/rateModels/EarnerRateModel.sol

@@ -16,7 +16,7 @@ import { IEarnerRateModel } from "./interfaces/IEarnerRateModel.sol";
 
 /**
  * @title  Earner Rate Model contract set in TTG (Two Token Governance) Registrar and accessed by MToken.
- * @author M^0 Labs
+ * @author M0 Labs
  */
 contract EarnerRateModel is IEarnerRateModel {
     /* ============ Variables ============ */
@@ -64,15 +64,20 @@ contract EarnerRateModel is IEarnerRateModel {
 
     /// @inheritdoc IRateModel
     function rate() external view returns (uint256) {
+        uint256 earnerRate_ = maxRate();
+        uint32 minterRate_ = IMinterGateway(minterGateway).minterRate();
+        uint240 totalActiveOwedM_ = IMinterGateway(minterGateway).totalActiveOwedM();
+        uint240 totalEarningSupply_ = IMToken(mToken).totalEarningSupply();
+
+        // If there are no active minters or minter rate is zero, do not accrue yield to earners.
+        if (totalActiveOwedM_ == 0 || minterRate_ == 0) return 0;
+
+        // NOTE: If `earnerRate` <= `minterRate` and there are no deactivated minters in the system,
+        //       it is safe to return `earnerRate` as the effective rate.
+        if (earnerRate_ <= minterRate_ && totalActiveOwedM_ >= totalEarningSupply_) return earnerRate_;
+
         return
-            UIntMath.min256(
-                maxRate(),
-                getExtraSafeEarnerRate(
-                    IMinterGateway(minterGateway).totalActiveOwedM(),
-                    IMToken(mToken).totalEarningSupply(),
-                    IMinterGateway(minterGateway).minterRate()
-                )
-            );
+            UIntMath.min256(earnerRate_, getExtraSafeEarnerRate(totalActiveOwedM_, totalEarningSupply_, minterRate_));
     }
 
     /// @inheritdoc IEarnerRateModel