LONDON—Global securities regulators began reviewing on Thursday whether to toughen up operational resilience at exchanges and other market infrastructure in light of the extreme trading volatility in 2020 when economies went into lockdown amid the pandemic. While much trading is already electronic, the curbs led to the New York Stock Exchange and London Metal Exchange temporarily closing their floors at a time when trading in markets was at its most volatile since Black Monday in 1987 in the United States. Current resilience requirements for exchanges, clearing houses, and settlement systems worked well, but there are opportunities for further improvements, the International Organization of Securities Commissions (IOSCO) said in a statement. There is a need for greater automation and less dependence on physical documents and manual processes to better accommodate people working from home, said IOSCO, which groups market regulators from the United States, Europe, Asia, and Latin America. Business continuity …