New York (CNN Business) The US dollar index reached a three-year high as investors worried about the global coronavirus outbreak are moving their money into the safe-haven greenback.

But the United States, as well as dollar-denominated assets, are considered to be somewhat shielded from the outbreak's impact.

America's economy is less reliant on trade and exports than its peers, for example. That means the expected slowing of China's economic growth in the first quarter will hurt the United States less than it will other countries.

And the US economy has been going strong and is in its longest expansion in history.

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