Roughly $1.7 trillion was erased from the S&P 500 at the start of US trading on Thursday amid worries that President Donald Trump’s sweeping new round of tariffs could plunge the economy into a recession. The index is on the brink of a crucial technical inflection point that threatens a longer-term wipeout. 

The damage was heaviest in companies whose supply chains are most dependent on overseas manufacturing. Apple, which makes the majority of its US-sold devices in China, plunged after the open – even after a yearslong effort to insulate itself from trade wars.

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• This is the formula Trump’s team used to calculate tariffs
• US emerges as the biggest loser in markets
  

• Trump just gave China’s Xi a chance to win over the world

• The US 10-year yield dropped below 4% for the first time since Trump won

Economists are still trying to get a handle on how much harm the US tariffs will do around the world. Learn more about the risks in today’s edition of Supply Lines, a newsletter exclusively for Bloomberg.com subscribers.