The reason for the sharp decline has been identified: a major Hong Kong-based institution experienced a margin call. Yesterday, BlackRock's IBIT trading volume reached $10.7 billion, nearly double the previous record high day, with options premiums around $900 million, both hitting historical records. $BTC and $BTC declined simultaneously, coupled with lower CeFi liquidations, leading to suspicion that this volatility was triggered by large positions held by IBIT major holders, possibly one or more non-crypto hedge funds headquartered in Hong Kong. Data shows that some funds held extremely large positions in IBIT, even as single-asset funds, aiming to isolate margin risk. Silver prices plummeted today, with yen arbitrage trades accelerating liquidations, intensifying market pressure and further impacting fund leverage positions. These funds may have attempted to turn the tide through highly leveraged options trading, but losses kept mounting, ultimately causing Bitcoin's decline to potentially completely wipe out their positions. Due to the delayed disclosure of 13F reports, related holdings are expected to be revealed by mid-May, but given the scale of the event, it will be difficult to hide it in the long term.