“In the US, you’ve got a Trump effect,” Mr Hayek said in an interview with Swiss newspaper Der Bund.
“This has unsettled a country whose economy is actually in relatively good shape.”
Mr Trump, the frontrunner to secure the Republican Party’s presidential nomination, threatens the US economy as restrictions on trade would ultimately hurt consumers, Thomas Donohue, chief executive of the US Chamber of Commerce, said last week.
Mr Trump’s proposal to prevent Muslims from entering the US would worsen a decline in tourist-generated retail sales, according to Melissa Avstreih, a Bloomberg Intelligence analyst.
A shaky global economy is already taking a toll on luxury-goods makers like Tiffany.
Sales at the brands Marc Hayek manages — which also include Blancpain and Jaquet Droz — may rise or fall as much as 5% this year in Swiss franc terms.
While Mr Trump’s plan to deny Muslims entry probably would not become law, the rhetoric alone may deter Muslim tourists from visiting the US.