Cyber hack of Industrial and Commercial Bank of China’s US broker-dealer rocks Wall Street

The cyber hack of Industrial and Commercial Bank of China’s US broker-dealer was so extensive on Wednesday that even the corporate email stopped working and forced employees to switch to Google mail, according to two people familiar with the situation.

The blackout left the brokerage temporarily owing BNY Mellon $9 billion, an amount many times larger than its net capital, a measure of resources at hand to promptly satisfy claims.

Those details and what happened next, some of which are reported here for the first time, show how the ransomware attack pushed the firm owned by China’s largest bank close to the brink.