Altria once again slashed the value of its stake in Juul on Thursday, as the once high-flying e-cigarette company faces lawsuits and a regulatory crackdown.

The owner of Marlboro and other leading cigarette brands, Altria announced a huge $4.1 billion write-down on its Juul investment, which follows a similar move in October that whacked $4.5 billion off the value on its books.

Since October, "the number of legal cases pending against Juul has increased by more than 80 percent," Altria said. "Litigation is subject to uncertainty and it is possible that there could be adverse developments in pending or future cases."

The announcement is the latest setback since Altria announced a $12.8 billion investment for a 35 percent stake in Juul in December 2018, a time when Juul's e-cigarette business was seen as a promising venture to counter amid weak demand for traditional tobacco products.

But last year Washington, DC, and the state governments of California and New York all sued Juul labs for targeting youngsters with its marketing campaigns.

Vaping came under additional scrutiny in late summer due to a health scare over cases of severe and sometimes deadly lung ailments, although that was later linked to a substance used in cannabis products.

In December, the US Congress voted to raise the minimum age to buy tobacco and e-cigarettes from 18 to 21 across the country.

Altria announced another huge writedown of its stake in Juul as the formerly high-flying e-cigarette company faces lawsuits and a regulatory crackdown
Altria announced another huge writedown of its stake in Juul as the formerly high-flying e-cigarette company faces lawsuits and a regulatory crackdown AFP / EVA HAMBACH

On January 2, the US Food and Drug Administration announced it was banning most flavored e-cigarettes, but stopped short of a full ban of vaping products.

Besides the hefty charge, Altria said it had also revised the terms of its agreement with Juul.

Under the new agreement, Altria will continue to provide assistance to Juul on regulatory affairs services, but will by the end of March 2020 "discontinue" other services.

Under the December 2018 announcement, Altria was to provide Juul access to Altria's retail shelf space and assist with other logistics and distribution activities.

The new agreement also allows Altria to develop its own vaping products if Juul is prohibited from selling e-cigarettes in the US for at least a year.

Shares of Altria slumped 4.9 percent to $47.66 in late-morning trading.