According to a recent report by Glassnode, Binance holds 85% of its Bitcoin (BTC) in outputs that are vulnerable to quantum attacks, while Coinbase Global Inc. maintains a significantly lower rate of 5%. Overall, 6.04 million BTC, which is 30.2% of the total Bitcoin supply, is classified as quantum exposed due to public keys being visible on the blockchain. This vulnerability arises from two main sources: structural exposure, affecting 1.92 million BTC (9.6%), and operational exposure, impacting 4.12 million BTC (20.6%). The latter is primarily due to address reuse, where spending from an address reveals the public key, thus exposing any remaining balance. Notably, exchanges account for 1.66 million BTC in operationally unsafe outputs, representing 40% of all operationally unsafe Bitcoin. In contrast, institutions like Fidelity and CashApp exhibit only 2% quantum exposure, while Robinhood shows a concerning 100%. Governments such as the U.S., U.K., and El Salvador have successfully maintained 0% quantum exposure through effective address management practices. Glassnode emphasizes that while this data highlights custody design issues, it does not indicate immediate risk for any exchange.