A growing number of Bitcoin whales are relinquishing their private keys and exchanging their BTC for BlackRock's Bitcoin ETF shares. BlackRock revealed that approximately $3.6 billion worth of self-custodied Bitcoin has been directly converted to IBIT, primarily for security reasons. This year, wrench attacks targeting large cryptocurrency holders have increased by more than 30%, with hardware wallets like Ledger and Coldcard experiencing attacks, and even leading exchanges like Binance not being spared. However, proponents of self-custody are not convinced, arguing that entrusting coins to Wall Street goes against the original purpose of Bitcoin. Furthermore, with approximately 90% of the assets in mainstream Bitcoin ETFs held by Coinbase, the concentration risk is also significant.