Since 2009, Altria's revenue has grown 9 percent, to $25.58 billion from $23.56 billion. But Altria's U.S. cigarette volume has nearly halved — to 116.6 billion units in 2017 from 211.9 billion units in 2000.
And Altria currently makes the bulk of its money selling cigarettes. Of the $25.58 billion in total revenue the company generated last year, $22.64 billion — or 89 percent — came from its smokeable products business segment, which contains cigarettes and cigars.
On average, Altria's cigarette volume decreases 3 percent every year, according to a review of the company's financial statements. The company has managed to offset these declines through price increases. However, the declines have started accelerating, worrying some analysts and investors they may be unsustainable.
Shares of Altria are down about 24 percent this year.
In the first nine months of this year, Altria's cigarette shipment volume fell 6.3 percent. On a call with Wall Street analysts in October, Altria CEO Howard Willard attributed at least part of the trend to more smokers giving up conventional cigarettes and switching to e-cigarettes.
Right now, when smokers ditch Marlboro for Juul, Altria loses out. That will change if Altria owns a portion of Juul.
Plus, Juul pods may be more profitable than conventional cigarettes because they typically aren't taxed and don't have to pay costs associated with the Master Settlement Agreement (MSA), a deal negotiated in 1998 between tobacco manufacturers and state attorneys general that ended a wave of ongoing lawsuits.
An average pack of cigarettes in the U.S. cost consumers $6.60, according to a research note from Piper Jaffray analyst Michael Lavery. State and local excise taxes on that pack typically equal $1.75, he wrote, while costs associated with the MSA total 75 cents. Manufacturers' operating profit usually comes out to $1.26, Lavery said.
Juul doesn't pay the approximately $2.50 in MSA costs and taxes that Altria pays. So far, 10 states have adopted e-cigarette taxes, according to the Campaign for Tobacco-Free Kids.
A pack of four Juul nicotine pods costs $15.99, or about $4 per pod, on the company's online shop. The amount of nicotine in each pod is equivalent to one pack of cigarettes. So while it's unclear how much money Juul makes on each pod since the company is private, Juul appears to have an advantage.
Pressure has mounted on Juul, with regulators demanding the company fix "epidemic" levels of minors using the company's products. However, Altria is used to navigating regulation and litigation. And it may decide the risks are worth taking.
Altria on Friday also announced it would invest $1.8 billion to buy a 45 percent stake in Cronos. As an investor, Altria said it will provide Cronos with its expertise in regulatory affairs, regulatory science, compliance, government affairs and brand management.
If Altria also invests in Juul, it's likely the company could provide the same services.
Altria is also awaiting a decision from the FDA on Philip Morris International's new heated tobacco product, iQOS. The device heats tobacco instead of burning it, with the idea that it gives smokers the nicotine they want while preventing combustion, the chemical process responsible for producing toxins in cigarettes. PMI already sells iQOS in 46 markets overseas.
PMI has two separate applications into the FDA: one that would simply allow it to sell iQOS in the U.S. and one that would allow it to market the product as less harmful than smoking conventional cigarettes. The company has said it expects a decision by the end of the year. If the FDA clears the product, Altria will sell it in the U.S.
Altria declined CNBC's request for comment.
contributed to this report
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