The US stock market is down almost 10% since President Donald Trump’s inauguration, marking the worst 10-week start under a new president since George W Bush in 2001 during the height of the dot-com selloff.The S&P 500 Index is virtually in a correction over the 52 trading sessions since Trump swore the oath of office January 20. More than $3tn has been erased from the index’s value over that stretch. That’s worse than the start to the prior five administrations, only exceeded by the roughly 18% drop in Bush’s first term.While 52 days is an arbitrary waypoint — and presidents have limited direct impact on the stock market — Trump touted on Wednesday as a landmark in US history, calling for the tariffs to “Make America Wealthy Again.”Instead, the announcement of the steepest levies in a century sparked a rapid selloff in risk assets, culminating Thursday with a 4% rout in the S&P 500. Meanwhile, economists have been furiously raising the odds for a recession and warn that inflation may spike higher.“What you’re seeing is the market of reaction to just how much has changed in that short period of time,” Brian Mulberry, client portfolio manager at Zacks Investment Management Inc, said. “What we’ve been seeing is just investors’ reaction on certainty versus uncertainty.” Traders sold off a broad range of US equities Thursday morning as the new round of tariffs sparked fears that the levies will slow growth and push the economy into a recession. Trump placed levies of at least a 10% on all exporters to the US on Wednesday, with higher amounts on specific countries and regions, including China, Vietnam, Japan and the European Union.The president has long seen tariffs as a tool to bolster US power globally and bring manufacturing jobs back onshore. But the breadth and severity of the current round outpaces anything seen in his first term.Indeed, some Wall Street pros speculated about a “Trump Put,” where he wouldn’t do anything to severely harm the stock market, which he has often used as a scorecard for success. But in this case it’s his own policies that are causing the damage.Some of the steepest losses are in the shares of companies and sectors tied to countries facing the steepest tariffs. Shares of China-exposed Apple Inc fell more than 9%, erasing over $260bn in market value. Lululemon Athletic Inc and Nike Inc are each down roughly 13%, alongside other companies with manufacturing tied to Vietnam.“We won’t know what makes any of those go lower until we start hearing about what negotiations are going on. And that’s the job of the weeks ahead unfortunately,” Art Hogan, chief market strategist at B Riley Wealth Management, said. “So we removed one layer of uncertainty only to bring another layer of uncertainty.”