Two telecom lines fail to protect world’s top derivative bourse

Less than an hour into trading in India’s $2.7 trillion stock market on Wednesday, dealers saw index levels on the National Stock Exchange’s cash segment had stopped updating. By 11:40 a.m., the world’s biggest derivatives bourse halted trading in all segments.

The incident prompted the markets regulator to ask the NSE to investigate why trading didn’t migrate to its disaster-recovery site to prevent the longest-ever trading outage the country has seen. The exchange handles the globe’s highest number of futures and options contracts, and with expiry looming Thursday, business was humming.

The NSE’s engineers had also been a busy lot that morning. When they found that their lease-line data pipes weren’t transferring, they decided that systems need to restart, according to people with knowledge of the matter.