Stock market investors may be underappreciating risk tied to President Donald Trump’s tariff policy, according to Cboe Global Markets’ top volatility expert Mandy Xu. The CBOE Volatility Index , a measure of stock market volatility over the next 30 days, is down nearly 50% from the peak of 60.13 it hit Wednesday. Even though the move coincides with the recent rebound in equities, Xu contends the market gyrations aren’t over just yet. The macro outlook is a lot more uncertain going forward than what is priced into the equity market right now,” the firm’s derivatives market intelligence head told CNBC’s ” Fast Money ” on Monday. Xu highlights an “unusual” circumstance where bond yields have moved higher along with stocks, with the 10-year Treasury Note yield briefly topping 4.5% on Friday as investors fled U.S. assets. “Our VIX [20+ Year Treasury] TLT indicator, which measures volatility in the bond market, went up 60 points last week. It’s retraced a little bit today, but it’s still near multi-year highs,” Xu added. The heightened activity could be flashing a warning signal about the macroeconomic environment, according to Xu. “What we’re seeing is more demand for puts in TLT, positioning for yields to go higher,” she said. “That really indicates an erosion of confidence in U.S. markets right now.” On “Fast Money” in early March, Xu warned the stock market was underpricing tariff risks . She also noted the bond market was signaling a potential recession. ‘The perfect storm’ “Fast Money” trader Dan Nathan is chalking up the current heightened volatility backdrop to panic caused by tariff uncertainty. “I don’t think a lot of people were hedged up, and they were reaching for it once they saw a lot of different asset classes go haywire together,” Nathan told “Fast Money.” “Obviously, that’s the dollar , that’s yields and the stock market. [It] was kind of the perfect storm.” When it comes to the market swings, Nathan suggests it may be worth waiting to buy downside protection on the S & P 500 . “There’s a lot of overhead resistance, technically, in this 5,750, 5,800 level, and I think you’ll see a lot of folks put on protection there.” On Monday, the S & P 500 closed at 5,405. Join us for the ultimate, exclusive, in-person, interactive event with Melissa Lee and the traders for “Fast Money” Live at the Nasdaq MarketSite in Times Square on Thursday, June 5 th .