A lot of people will be working at those companies and it's a very safe bet that tens of thousands Canadians have smoked pot.
Anyone subject to a lifetime ban from entering the United States can apply for a waiver, though that costs more than $500.
In a piece titled, "U.S. Border Policy on Pot Is About to Get Even Stupider", Splinter's Sophie Weiner points out that upcoming "midterms could change all of this".
The rub is that it's illegal to have smoked the drug in Canada before October 17, and it's illegal to lie to any border agent who asks about it.
CBP has not specified a minimum investment threshold in marijuana businesses that would trigger the lifetime ban. US border officials have warned Canadians who smoke marijuana, work in the cannabis sector - or even invest in burgeoning pot companies could be barred entering the country. Until his comments, the BI Canada Cannabis Competitive Peers index had gained almost 50 percent since the Canopy-Constellation deal was announced.
But Prime Minister Justin Trudeau said Tuesday that he does not think he has the right to press the US on its admission policy.
So what to do when you want to cross the border?
Volkswagen to end production of the Beetle next year
The iconic bug-inspired auto that made the Volkswagen vehicle so endearing in India will no more be produced by its manufacturer. The group has no immediate plans to revive the Beetle again, but the company wouldn't rule it out.
Human case of West Nile virus identified
Symptoms of the more serious West Nile encephalitis include inflammation of the brain, disorientation, convulsions and paralysis. Applying an insect repellant with DEET, IR 3535, picaridin, or oil of lemon eucalyptus to clothing as well as exposed skin.
Death toll rises to 7 as Florence pours on the rain
He said parts of North Carolina had seen storm surges - the bulge of seawater pushed ashore by the hurricane - as high as 10 feet. In Washington, North Carolina, the wind-swept Pamlico River has risen beyond its banks and is flooding entire neighborhoods.
They say that despite one in eight Canadians using cannabis today, 400,000 people move between our two countries every day nearly entirely without incident.
Despite that Canada will have legal cannabis nationwide in a month, and that a majority of states have legalized cannabis to some extent, the plant remains illegal at the federal level. That message hasn't "fully sunk in" yet, especially with more casual tourists, said Continental Travel Group President Daryl Silver.
Cars from Canada line up to cross into the U.S.at Blaine, Wash.
Canadians spent $19.8 billion on tourism south of the border in 2016, according to the International Trade Administration.
"People are careless and I think people will be caught by accident and this will create problems", said Lorne Waldman, an immigration lawyer.
"We don't recognize that as a legal business", Todd Owen, executive assistant commissioner for the Office of Field Operations at CBP, told POLITICO Pro Canada, a new subscription news service and daily newsletter focused on Canada-U.S. relations.
"There's absolutely no way you can say if you've invested in the is industry you're not going to be allowed into the United States", he said.
"You're not just going to see these northern Washington cases, you're going to see them Canada-wide from east to west coast", he said.