Cigarette sales dropped by 11 percent in the four-week period ending May 18, according to leading market research company, Nielsen.
The vape sector rose by 46 percent over the same period, with JUUL accounting for over 74 percent of sales.
Total cigarette sales have now declined for 18 consecutive months.
Shares in Philip Morris USA parent company Altria dropped by 5 percent on Monday while British American Tobacco (BAT) shed 4 percent.
Altria acquired a 35 percent stake in JUUL in December last year. However, Cowen analyst Vivien Azer said that increased JUUL sales have not offset Altria’s cigarette losses.
“For every pack of Marlboro that converts to Juul pods, Altria loses 100% of Marlboro and gains 35% of the Juul pod.
“There’s no way the math is possible for that to be a perfect offset.”