The Cboe Volatility index jumped on Thursday, returning back above its long-term average level as the U.S. stock market sold off broadly amid concerns about trade and ongoing weakness in the technology sector. The VIX VIX, +15.01% climbed 23%, or 4.18 points, to 22.04, putting it on track for its biggest one-day pop since Feb. 5, when it more than doubled off historically low levels. The so-called "fear index," which generally moves inversely to the stock market, climbed as the Trump administration's plans to announce new trade restraints against China, renewing fears about a potential trade war that could dent economic growth. Ongoing weakness in Facebook Inc. FB, -1.90% added to the negative tone in equities. The Dow Jones Industrial Average DJIA, -1.84% fell 1.9% on Friday while the S&P 500 SPX, -1.62% lost 1.7%. The Nasdaq Composite Index COMP, -1.53% fell 1.9%. The VIX, which reflects bullish and bearish S&P 500 options wagers 30 days out, has more than doubled in 2018, having risen 102.5%.