Former Treasury Secretary Lawrence Summers has urged the Securities and Exchange Commission (SEC) to conduct an investigation into the historic surge in the Cboe Volatility Index (VIX) that occurred on Monday. What Happened: Summers speculated that the unusual VIX movement could be due to the influence of illiquid instruments used in its calculation. The VIX, often dubbed the “fear gauge,” is a barometer of anticipated stress in U.S. equities. Amidst a sharp selloff in stocks on Monday, the VIX saw an unparalleled surge, soaring over 65, a level that signals extreme investor panic. According t…