Crypto Trader Loses Nearly $50M in Aave Trade, Protocol Offers $600K Fee Refund

A crypto trader lost almost the entire value of a $50 million transaction on Thursday after executing a large swap for Aave’s governance token through the decentralized finance protocol’s trading interface.

The user attempted to buy AAVE with $50 million worth of the stablecoin USDT through the Aave interface, according to a statement posted on X by Aave founder Stani Kulechov. 

Because the order was unusually large relative to available liquidity, the interface issued a warning flagging “extraordinary slippage” and required the user to manually confirm the risk.

The trader then proceeded with the swap on a mobile device after checking a confirmation box.

That transaction ultimately returned just 324 AAVE tokens. At a current market price of $111.52, the tokens are worth roughly $36,100, implying an effective loss of about $49.96 million relative to the original order size.

Aave engineer Martin Grabina said the issue wasn’t slippage itself but the price impact of the order, noting the trade quote already implied that $50 million in USDT would return fewer than 140 AAVE tokens before fees.

“In this case, the user sent a market order with the suggested 1.21% slippage,” Grabina wrote on X. “But the core issue wasn’t slippage, it was just the accepted quote with 99% price impact: As you can confirm it yourself on the CoW explorer, the order includes a quote field showing the original rate (50M USDT -> <140 AAVE) presented to the user before fees and slippage. It was already a very bad rate."

Kulechov said the Aave team will attempt to contact the trader and return approximately $600,000 in fees generated by the transaction.

By design

Kulechov said the trade was routed through CoW Swap, a decentralized trade-routing system integrated into the Aave interface, and that the infrastructure functioned as designed.

“The transaction could not be moved forward without the user explicitly accepting the risk,” Kulechov wrote. “However, while the user was able to proceed with the swap, the final outcome was clearly far from optimal.”

Large trades executed through decentralized exchanges can cause severe price impact when liquidity is insufficient or when orders are not broken into smaller increments. 

Professional traders typically split large orders across multiple transactions or use execution algorithms to reduce market impact or minimize slippage. 

Kulechov said the incident shows how decentralized finance platforms may need stronger guardrails to help prevent extreme user errors while preserving permissionless access.

“Our team will be investigating ways to improve these safeguards going forward,” Kulechov said.

The incident comes as Aave’s usage has surged.

Monthly active users on the lending protocol reached about 155,000 in February, an all-time high and nearly double the level six months earlier, according to Token Terminal data previously reported by Decrypt.