BigONE detected abnormal asset movements on July 16 and said a third-party attack had targeted part of its hot-wallet assets. The exchange stated that private keys remained secure, the attack path had been identified and contained, and no further losses were expected. BigONE estimated losses at about $27 million, including USDT on TRC20 and ERC20, while working with SlowMist to trace hacker addresses and monitor fund movement. The incident matters for exchange-security tracking because it combines hot-wallet compromise, fund-tracing response, and user-compensation measures through internal reserves and external liquidity.