View from watchtower as the pennies fall

Singapore

ON Oct 4, 2013, Kelvin Koh, head of surveillance regulation at the Singapore Exchange (SGX), was at work by 8am, just a little earlier than usual; he would not leave for home that day until about 10pm, though.

When the markets opened at 9am, the stocks of a few counters began to collapse - wiping out hundreds of millions of dollars of market value and sending a shock wave across the market. In the next half-hour, SGX sent out a number of trading queries.