A decade ago, the flash crash of 6 May 2010 rocked markets. What followed was a broad effort by regulators and Wall Street to fix the complex electronic systems that underpin the US stock market — moves that appear to have paid off in the recent coronavirus-induced nosedive.

The March turmoil caused the S&P 500 to suffer its swiftest-ever decline from a record into a bear market. Despite the meltdown and extreme volatility, the market’s plumbing held up, a largely unsung success that drew little notice among Americans focused on the pandemic.