Shares of Circle Internet Group CRCL, Robinhood Markets HOOD and Coinbase Global COIN fell 5.93%, 6.17% and 5.33%, respectively, in premarket after Binance said a security incident had an estimated impact of $6.3 billion, the biggest crypto hack on record. Bitcoin fell more than 4% to below $78,000.

Binance, the world’s largest crypto exchange, said about $3 billion of the affected assets had been frozen, and pledged to cover all losses with its Secure Asset Fund for Users and company funds. An initial investigation pointed to a compromised engineer’s laptop that let an attacker submit unauthorized withdrawals, though co-CEO Richard Teng later said the attack was a complex process, not one engineer’s misuse of permissions. We have found…