An unidentified crypto whale has repeatedly removed about $290 million in USDC from Aave and Sky, temporarily reducing available liquidity and increasing borrowing costs. Bitquery, a blockchain analytics firm, reported on October 28 that the transfers happened near midnight UTC. Bitquery said approximately $134 million was withdrawn from Aave, while Sky supplied the balance. The money generally returned roughly 30 minutes later.
The recurring withdrawals brought Aave's USDC lending pool close to full utilization, limiting withdrawals by other depositors and nearly tripling borrowing rates. During October, the pool's median utilization increased from 94% to 99.6%, leaving almost none of the deposited funds unborrowed. Utilization reached 100% on six nights, leaving depositors almost no unborrowed USDC to withdraw.
Before the October 26-27 withdrawals, Aave held approximately $173 million in available USDC liquidity. The unidentified holder withdrew $134.1 million, about 78% of the available funds. Other depositors then had access to less than $46 million in immediately withdrawable USDC until the funds came back. Aave's automatic interest-rate adjustments increased borrowing costs in response to the liquidity shortage.
Bitquery found that the median annualized USDC borrowing rate increased from 4.5% before the withdrawals to 13.8% afterward. Borrowing rates declined after the money returned. The rate increases persisted only during the liquidity shortages, limiting the extra interest borrowers actually paid.
Bitquery said the wallet cluster responsible had transferred USDC across midnight on 394 consecutive nights since September 30, 2025. The earliest midnight transfers identified dated to July 2024. The wallet owner's identity and purpose remain unknown.
The timing initially generated speculation about exploiting stablecoin reward programs that use balances recorded at particular times to calculate earnings. Bitquery noted that the withdrawn USDC repeatedly gathered in a single wallet across midnight. Bitquery said that arrangement could benefit the holder if rewards depended on a daily balance snapshot. However, Coinbase does not make the timing of USDC reward calculations public. Investigators could not establish whether the wallet obtained any extra payments.
Aavescan data showed that the pool's borrowing rate declined from 13.27% at midnight UTC on October 28 to 5.45% on October 29. The lower rate points to a milder liquidity shortage in the latest observed period. Bitquery has not identified the wallet owner or determined whether the repeated transfers will persist.