Canadian investors have poured $59.9 billion Canadian dollars ($43.3 billion USD) into net purchases of U.S. debt and equities from January to May this year alone, according to data from the National Bank of Canada Financial Markets, the most in this year-to-date period since at least 1990. Meanwhile, net foreign investment in Canadian securities fell by $18 billion CAD ($13 billion USD) in the first five months of the year.

“‘Buy Canadian’ programs seemingly don’t apply to investment portfolios, as Canadian investors have instead loaded up on U.S.-issued securities at an entirely unprecedented year-to-date pace,” Warren Lovely, managing director of National Bank Financial, wrote in a report last month. “Meanwhile, foreign investors have cooled on Canada.”

The Canadian flocking to American stocks comes as U.S. markets continue to outperform the benchmark, despite widespread concerns about tariff-induced inflation, a cooling labor market, and an AI bubble. Ironically, Canadian stocks are actually outperforming their American counterparts, according to Morningstar data, possibly a result of Canadian company valuation bases starting the year much lower than those in the U.S. 

While Canadian stock growth could imply continued investment from Canadians, the magnitude of the U.S. market makes it nearly impossible to resist.

“Canadians continue to invest in the United States because Canada is a relatively small market, and any fully diversified approach to investing requires continued allocations to the U.S. market,” Brett House, a professional practice professor at Columbia Business School and fellow with Canada’s Public Policy Forum, told Fortune.

Why has ‘Buy Canadian’ drawn the line at stocks?

According to Moshe Lander, a former senior economist for the Government of Alberta and a senior lecturer of economics at Concordia University in Montreal, the desire to invest in U.S. companies despite also wanting to rebuff American companies through boycotts serve separate functions. 

“The U.S. boycott is an emotional thing, not an economic thing,” Lander told Fortune. “A lot of Canadians have realized that there’s a limit to how far they’re prepared to voice their objections.” 

While refusing to buy consumer products from the U.S. is a way to make Canadians feel empowered through their everyday actions, Lander said the same will to slight U.S. companies doesn’t make as much sense to investors more concerned with the pragmatic places to put their money. There’s another practical reason for continued U.S. stock purchases, according to Lander: Most Canadians don’t manage their own investment portfolios, leaving it instead to financial advisors, who are not making the same emotion-based decisions as boycotters.

“When I go to the grocery store, I can choose to not buy an American product,” Lander said. “When I talk to my financial advisor, I’m not instructing them to stay clear of Apple, Microsoft, and Walmart.”

The limitations of the ‘Buy Canadian’ movement

Still, the act of boycotting, however emotionally provoked, has made its mark on the U.S. In late March, Air Canada reported a 10% drop in bookings to U.S. cities compared to the same period in previous years. According to an analysis by Spirits Canada, U.S. spirit sales in Canada dropped 66.3% between the beginning of March and the end of April, the period in which several retailers said they would stop selling American booze, according to an analysis by Spirits Canada.

“It’s been an effective way for Canadians to show they’re upset with the great insults that the Trump administration has visited upon both the Canadian government and the Canadian people,” Columbia’s Brett House said.

However, Lander sees the “Buy Canadian” movement dying down as it becomes less sustainable for the Canadian economy. Canada’s annual imports and exports are each worth roughly half-a-trillion dollars, Lander said. If Canadians were to aggressively commit to a boycott, that $500 billion hit would mean little for the U.S. GDP nearing $30 trillion, but would take a meaningful chunk out of Canada’s $2 trillion economy.

“I don’t know that it’s as much the continued purchase of U.S. equities or bonds as being the anomaly,” Lander said. “It’s more the fact that the boycott of American goods and tourism has actually managed to succeed for seven months.”