Trump initially sparked hysteria in the financial markets by announcing tariff rates on dozens of countries, including 24% on Japan and 25% on South Korea. In order to calm the markets, Trump unveiled a 90-day negotiating period during which goods from most countries were taxed at a baseline 10%.

In letters so far to 14 countries, including smaller exporters to the United States such as Serbia, Thailand and Tunisia, Trump hinted at opportunities for additional negotiations, even while warning that reprisals would draw a like-for-like response.