A user attempting to swap $50 million worth of USDT for AAVE through the interface of the decentralized finance protocol Aave ended up receiving only 324 AAVE after accepting a quote with an extreme price impact, prompting the platform to review safeguards and refund a portion of the transaction fees. Summary A trader swapping $50M USDT on Aave received only 324 AAVE after accepting a quote with roughly 99% price impact. Aave says warnings were shown and manually confirmed before the trade executed. The protocol plans to refund about $600K in fees and review additional user-protection safeguards. One checkbox, $50 million gone: Inside a disastrous Aave trade Aave founder Stani Kulechov said the unusually large transaction triggered warnings on the interface before the trade was executed. According to Kulechov, the user was alerted about extraordinary price impact and had to manually confirm the risk via a checkbox before proceeding with the swap on a mobile device. “Events like this do occur in DeFi, but the scale of this transaction was significantly larger than what is typically seen in the space,” Kulechov said in a post on X. He added that the platform would attempt to contact the user and return approximately $600,000 in fees collected from the trade. The transaction was routed through CoW Swap, whose auction-based mechanism is designed to find the best available liquidity across decentralized exchanges. Kulechov said the routing infrastructure functioned as intended and followed standard industry practices, even though the final outcome for the trader was “far from optimal.” Aave engineer Martin Grabina later clarified that the issue was not related to slippage settings, a tolerance that allows prices to deviate slightly between order signing and execution, but rather the extremely unfavorable quote the user accepted. Of course, we’re working with @CoWSwap to understand why the solvers and liquidity sources produced this rate— martin (@mgrabina) March 13, 2026 According to Grabina, the order carried a roughly 99% price impact from the outset, meaning the quoted exchange rate itself was already highly unfavorable. The user submitted the market order with the interface’s suggested slippage tolerance of 1.21%, while analytics data showed the trader even received a small 0.7% surplus from the auction mechanism. Grabina said the interface displayed a clear price-impact warning before execution and required explicit confirmation. The Aave team said it is now working with CoW Swap to analyze why liquidity sources produced such a poor quote and to explore stronger safeguards that could help protect users while preserving the permissionless nature of decentralized finance.
