> ## Documentation Index
> Fetch the complete documentation index at: https://docs.derive.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Interest Rate Model

| Parameter | Contract Variable | Value | Description |
| - | - | - | - |
| MIN\_RATE | \`lending\_pools.irm.min\_rate\` | 0 | The borrow rate at zero utilization. |
| OPTIMAL\_UTIL | \`lending\_pools.irm.optimal\_util\` | 0.80 | The kink in the curve. Above it the rate rises far more steeply. |
| LOW\_SLOPE | \`lending\_pools.irm.rate\_at\_optimal\` | 0.048 | The borrow rate reached at \`OPTIMAL\_UTIL\`, i.e. 4.8% at 80% utilization. |
| HIGH\_SLOPE | \`lending\_pools.irm.rate\_at\_full\` | 1.0 | The additional rate charged between \`OPTIMAL\_UTIL\` and full utilization, so 104.8% at 100%. |
| SM\_FEE | \`lending\_pools.irm.sm\_interest\_fee\` | 20% | Share of interest paid by borrowers that is diverted to the Security Module. Rises to 100% while the Security Module is depleted. |


## Related topics

- [public/get_interest_rate_history](/api-reference/market-data/publicget_interest_rate_history.md)
- [Rate Limits for Integrators and Market Makers](/integrators/trading/rate-limits.md)
- [Rate Limits](/rate-limits.md)


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