What happened

Shares of National Beverage Corp. (FIZZ -2.29%) gained 13.4% in January 2018, according to data from S&P Global Market Intelligence. The maker of LaCroix flavored water was honored by PepsiCo (PEP -0.41%) and Nestle (NSRGY -1.55%) launching new products to compete head-to-head with this far smaller company.

So what

First, Pepsi unveiled a line of sparkling, flavored waters under the Bubly brand name. Then, Nestle said it would bring in flavored versions of its six American water brands -- Deer Park, Zephyrhills, Arrowhead, Ice Mountain, Ozarka, and Poland Spring. Both Pepsi and Nestle will support their new water products with generous marketing budgets, and National Beverage shares rose significantly on both of these announcements.

A smiling young woman chooses between water in a can or a bottle, both unbranded.

Image source: Getty Images.

Now what

The rising interest in flavored water is seen as confirmation of LaCroix's heady market momentum. At this point, pretty much any beverage company worth its salt has some kind of plan to copy the LaCroix concept. National Beverage shareholders are reaping big rewards as LaCroix continues to move deeper into mainstream culture, and the stock has gained a market-stomping 67% over the last 52 weeks.