As Trump escalates his protectionist trade agenda, foreign citizens are taking matters into their own hands by boycotting US products and limiting tourism — a phenomenon that could significantly impact US growth and individual businesses.

In a note published on Monday, Goldman Sachs estimated foreign boycotts could amount to as much as 0.3% of domestic GDP, registering a hit of just over $83 billion based on current growth estimates of $27.7 trillion.

Goldman’s base case is closer to 0.1%, or nearly $28 billion.

“Most reports of boycotts of consumer goods have focused on Canada, where 53% of consumers claim to have started some form of boycott,” Goldman Sachs’ economics team led by Jan Hatzius said, citing a recent YouGov survey. “We expect a particularly large pullback in sales of American alcohol in Canada, since most of the provincial alcohol monopolies have removed US products from their shelves.”

Last month, Lawson Whiting, the CEO of Jack Daniel’s maker Brown-Forman (BF-B) said Canada’s decision to pull American-made spirits off its shelves was “worse than a tariff because it’s literally taking your sales away.”

On the travel side, Air Canada (AC.TO), which flies to the US more than any other Canadian competitor, said Monday that travel demand between the US and Canada is weak.

Bookings for trans-border flights between April and September are down 10% compared to the same period last year, according to company data compiled mid-March.

“Am I concerned? Yes. Definitely, I’m concerned,” Chairman Vagn Sørensen said.