Summary

This proposal introduces two updates on Ethereum:

1. Caps the borrow rate at maximum utilization to 15% (from the current 40%) for USDC, USDT, and GHO on the Liquidity Layer, keeping every other rate-curve parameter unchanged.
2. Reduces the Team Multisig (0x4F6F977aCDD1177DCD81aB83074855EcB9C2D49e) USDC and USDT borrow limits on the Liquidity Layer to the minimum (base 10 / max 20 wei), i.e. effectively 0.

Code Changes

Action 1: Cap USDC, USDT & GHO Borrow Rate at Max Utilization to 15%

• Calls LIQUIDITY.updateRateDataV2s() for USDC, USDT, and GHO (all three use rate model v2).
• Changes for every token:
  • rateAtUtilizationMax: 40% -> 15%
• Keeps unchanged (matching the current on-chain getTokenRateData(token) values):
  • USDC / USDT: kink1 = 85%, kink2 = 93%, rateAtUtilizationZero = 0%, rateAtUtilizationKink1 = 6%, rateAtUtilizationKink2 = 8%
  • GHO: kink1 = 85%, kink2 = 93%, rateAtUtilizationZero = 0%, rateAtUtilizationKink1 = 6.5%, rateAtUtilizationKink2 = 9.5%
• The Liquidity AdminModule requires rateAtUtilizationKink2 <= rateAtUtilizationMax; this holds for all three tokens (8% <= 15%, 9.5% <= 15%).

Action 2: Reduce Team Multisig USDC & USDT Borrow Limits to Effectively Zero

• Calls setBorrowProtocolLimitsPaused() for the Team Multisig with borrow tokens USDC and USDT.
• Lowers the borrow limit to ~0 (baseDebtCeiling = 10, maxDebtCeiling = 20, in wei). This sets the debt ceiling to a dust amount — it is not an operation-level borrow pause; borrowing is simply capped at ~0. Other config: mode = 1, expandPercent = 1 (0.01%), expandDuration = 16777215 (max).
• mode = 1 (with interest) matches the Team Multisig's existing on-chain borrow config for both tokens, so no mode switch is triggered.

Description

The first action makes the USDC, USDT, and GHO borrow curves substantially less punitive at the top end by lowering the rate charged at 100% utilization from 40% to 15%. Only rateAtUtilizationMax is changed; the utilization breakpoints (kink1 = 85%, kink2 = 93%) and the rates at zero/both kinks are read from the live Liquidity Layer rate config and re-supplied unchanged, so the shape of the curve below kink2 is preserved and only the final segment (kink2 -> 100%) flattens.

The second action drives the Team Multisig's direct USDC and USDT borrow capacity on the Liquidity Layer to effectively zero. Because the Liquidity AdminModule rejects a literal-zero baseDebtCeiling / maxDebtCeiling (reverting with LimitZero), the established convention of minimal "dust" limits (baseDebtCeiling = 10, maxDebtCeiling = 20, with the slowest possible expansion) is used to represent "0". Existing debt is not affected by the change; the reduced ceiling only blocks new borrowing beyond the dust amount.

Conclusion

IGP132 caps the USDC, USDT, and GHO max-utilization borrow rate at 15% (down from 40%) while preserving all other rate-curve parameters at their current on-chain values, and reduces the Team Multisig's USDC and USDT borrow limits on the Liquidity Layer to the minimum (base 10 / max 20 wei), effectively setting that borrowing capacity to 0.