A lot has happened in the 30-plus days since President Donald Trump threw the U.S. into a trade war, drawing retaliation after announcing on Feb. 1 that he was slapping a 25% tariff on imports from Canada and Mexico and a 10% tariff on imports from China.

The Trump administration’s subsequent rat-a-tat-tat of broadening tariff actions has been full of starts and stops punctuated by its negotiations with world leaders spilling into personal social media accounts. 

Among the changes: On Feb. 3 Trump agreed to pause tariffs on Mexico and Canada for 30 days after they agreed to strengthen borders against fentanyl trafficking; on Feb. 10 he tagged steel and aluminum imports with 25% tariffs; and last week signaled he’d soon announce 25% tariffs on cars and other goods from the European Union, and said he’d impose an added 10% tariff on China.  

Now, as March dawns, the tariffs on Canada and Mexico are poised to go into effect Tuesday. By Monday afternoon Trump had weighed in to assert they were going forward. “Tomorrow — tariffs 25% on Canada and 25% on Mexico. And that’ll start,” Trump told reporters in the Roosevelt Room, according to an Associated Press report. “They’re going to have to have a tariff.”

U.S. stocks fell in afternoon trading after Trump also said there was "no room left" for negotiatios with Canada and Mexico, The Wall Street Journal reported. 

But earlier in the day analysts and companies who have been grappling with looming uncertainty around the scope and size of Trump tariffs against one-time U.S. trade partners of Mexico and Canada — and used to last minute changes — were still uncertain how it would play out. Adding to that uncertainty were comments made by Commerce Secretary Howard Lutnick on Sunday that the tariffs would go into effect with the caveat that Trump would decide the duty levels, Reuters reported. 

That left finance leaders, economists, lawyers and investors tracking the effective date still parsing the possible outcomes just hours before the deadline. “It is really hard to say but if history repeats itself it will go down to the wire, or there may be some concessions such as a later start date or lower tariff rates in lieu of the 25% promised,” KPMG’s Andrew Siciliano, a U.S. national practice leader in the Big Four Firm’s trade and customs practice, said in an emailed response to questions Monday.

Alex Durante, a senior economist with the Tax Foundation in Washington, expects some type of tariffs to go into effect against Canada and Mexico Tuesday, though he believes that there’s still potential for them to be lower than the original 25% headline rate. “Maybe they got some sort of concessions and they’ll meet in the middle at around 10%,” Durante said in an interview Monday. “We updated all our modeling [on the tariffs] and we’ll be prepared to update them again tomorrow.” 

Durante wasn’t alone in his anticipation: the foreign exchange market was not pricing the 25% in and was instead suggesting either “smaller tariffs or another last-minute deal,” according to a Monday report from analysts at ING.  “The FX market saw Mexico as more likely to avert tariffs over Canada a month ago and appears to have a similar feeling now, having penalized the loonie more than the peso in the past week,” the report states. 

Whichever way the tariffs play out, the move is very significant because it affects two of the largest trading partners that the U.S. has, Durante said. In 2024, the value of imports into the U.S. from Canada and Mexico totaled about $1 trillion, or roughly a third of $3.3 trillion imports into the U.S., he said. “It’s definitely concerning.”  

Finance leaders can be proactive and develop short, medium and long-term strategies while they wait for the details on the tariffs to be finalized, Siciliano said. The starting place would be knowing and understanding your import data and conducting an impact analysis based on past transactions, he said. From there, companies can determine the most impacted products and supply chain lanes and identify whether alternatives are available as well as tariff mitigation strategies.

In contrast, the worst course of action is attempting to implement a non-compliant strategy, which can stem from not understanding where a company’s products and their components come from, he said. “We saw in 2018 where companies assumed goods were not a product of China because they were manufactured outside of China with Chinese components and ultimately had to pay the duties and penalties,” Siciliano said.   

Editor’s note: This story was updated with additional comments from President Trump and information on the stock market’s reaction to his remarks.