AAVE V4 introduces a major change in its lending model with the implementation of a Risk Premium, which redefines how borrowing costs are calculated in its liquidity system. Historically, AAVE's previous models grouped assets into collateral clusters, where borrowing costs were driven mainly by supply and demand dynamics within that shared market. This meant that borrowers with different risk profiles often faced similar interest rates, even if their collateral posed varying levels of risk to the overall liquidity pool. For example, a borrower using established collateral like ETH could access higher loan amounts and better terms compared to someone using a less stable asset like AAVE tokens. The article highlights how the existing system's reliance on parameters like loan-to-value ratios and liquidation penalties did not adequately address the ongoing risks posed by riskier collateral. Borrowers using higher-risk assets could still access the same capital at the same interest rates as safer borrowers, creating a mismatch between risk and pricing. This issue intensified with the transition to a hub-and-spoke architecture in AAVE V4, where liquidity is concentrated, making it essential to differentiate costs based on collateral risk. To mitigate these risks, AAVE V4 introduces the Risk Premium, which dynamically adjusts borrowing costs according to the collateral's risk profile. This includes assigning a Collateral Risk score for assets and a User Risk Premium for individual borrowing positions. By doing so, AAVE aims to ensure that higher-risk borrowers face appropriately higher costs, reflecting the true risk they bring to the liquidity pool. This shift is crucial for maintaining system stability as it aligns borrowing costs with the actual risk associated with different collateral types.