Wall Street’s $5.5 trillion triple-witching to test market calm

This quarter’s expiration comes as implied volatility on S&P 500 options is holding near the lowest level since before the coronavirus pandemic, with the US benchmark index riding the surge in shares of Nvidia Corp. and other artificial intelligence-linked companies. The expiration coincides with index rebalancing, when S&P Dow Jones Indices shuffles company weightings and ETFs that track its gauges make similar adjustments.