As stocks creep ever higher and spark bubble concerns, one other bubble appears to be popping: the gum market.
During the past five years, U.S. gum volume has shrunk by a fifth, according to a new report from Rabobank. Sales are off by 11 percent.
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What's causing American smacking's rapid decline?
The major driver appears to be the rise in mint sales, which increased almost 20 percent during the past five years, according to the bank. Still, the total category's sales still lags the size of gum.
"Those savvy mint marketers have matched gum in terms of selling us fresh breath, oral hygiene and low calories and then gone the extra mile by trumping gum on convenience and value," analysts wrote.
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Lower interest in gum among young consumers and a shift toward natural labels and away from the complicated ingredient lists of many products have compounded the gum market's woes.
"In an age where natural and clean labels are the ticket to success, the ingredients label of your typical pack of sugar-free gum sounds more like an alchemist's shopping list: sorbitol, gum base, maltitol, mannitol, hydrolysed starch hydrolysate, artificial and natural flavorings, acesulfame potassium, aspartame, sucralose, butylated hydroxytoluene, titanium dioxide, etc," the report observes.
High prices and too many launches have also caused confused consumers to retreat, according to the report.
While Rabobank says sales at gum market heavyweights Mars and Mondelez suffered last year, Hershey sales grew in 2013 to total 3 percent of the market.
—CNBC's Katie Little