At about 18.2, the Cboe Volatility index (VIX), an option-derived measure of expected S&P 500 volatility, sits comfortably below its long-run average of 19.5. The VIX is known as Wall

Street's fear gauge because it tends to drift lower as the S&P 500 rises, spiking usually when sharp stock market falls see traders rushing to buy protection through options. Note

how on the chart below, provided by Duality Research, a VIX around the 15 level marked February's record high as investors were so relaxed they felt little need to hedge against a

market retreat.