It's partly that a strong USD means that people are buying dollars or moving money to the US. More money to the US means less money to others. It's partly borr

It's partly that a strong USD means that people are buying dollars or moving money to the US. More money to the US means less money to others. It's partly borrowing. Lots of developing nations' loans are denominated in dollars. Meaning that they have to pay back the money in dollars since lenders worry that developing nations/peoples would just devalue their money to pay back their loans if the loans were in pesos, liras, etc. As the USD gets stronger, the loans become more expensive. https://www.ft.com/content/b0436678-4fa8-11e8-9471-a083af05aea7 https://www.ft.com/content/b0436678-4fa8-11e8-9471-a083af05a... Mexico had a scare just 2 years ago which Trump's election and the USD gaining a lot on the mexican peso. There were even talk of mexico collapsing if the USD continued to gain strength because of mexico dollar debt issuances.