More than 20,000 bankers, traders, and other workers are bedding down in office towers in Shanghai's Lujiazui district as they bid to keep China's giant financial hub ticking through a Covid-19 lockdown, according to local administration officials.

Brokerages, asset managers, and financial exchanges in Lujiazui - China's answer to Wall Street - rushed to summon key personnel to offices ahead of yesterday's lockdown in Shanghai, and prepared sleeping bags and basic supplies for overnight stays.

Some have also adopted...