According to Wu Blockchain, analyst Willy Woo cited the River Bitcoin Custody Report, stating that over the past 16 years, more than 3 million BTC have been lost due to custody issues. Among them, approximately 1.57 million BTC are presumed to be permanently inaccessible, while around 1.51 million BTC were lost due to exchange hacks, internal theft, and bankruptcies. The report notes that about 98% of permanently lost Bitcoin incidents occurred before 2020.