Trump Boosts New Tariff Rate to 15% a Day After Announcing 10%

President Donald Trump said he will increase the global 10% tariff he announced one day earlier to 15%, stirring up more economic turbulence as he lashed out at the US Supreme Court over its ruling that his preferred mechanism for applying tariffs was illegal.

“I, as President of the United States of America, will be, effective immediately, raising the 10% Worldwide Tariff on Countries, many of which have been ‘ripping’ the U.S. off for decades, without retribution (until I came along!), to the fully allowed, and legally tested, 15% level,” Trump said in a social-media post on Saturday.

Trump is ...