Analyst Amit Sharma also upgraded the price target to $410, implying a return of about 14% from Thursday's price around $360.80.
The company's flagship beer is Samuel Adams Boston Lager, but it also sells alcoholic ciders and seltzers under the Twisted Tea, Angry Orchard Hard Cider and Truly Hard Seltzer brand names.
"SAM is one of the rare staples growth investments that doesn't require a sizable multiple expansion to 'work' as merely a better assessment of its growth potential signals material upside from current levels," Sharma said in a Sept. 26 note.
Sharma said the company's per-share earnings could approach $13 next year, which is 20% above the current consensus of $10.78, citing, in particular, the popularity of its Truly Hard Seltzer.
The company recently announced a multiyear U.S. partnership with the National Hockey League making Truly Hard Seltzer the official hard seltzer of the league.
"Truly is primed to capture strong consumer demand and higher distribution/shelf space for hard seltzer, which, in our base-case scenario, could post 80% growth in 2020 and a +30% CAGR over the next five years," the analysts wrote, adding that Truly "is well-positioned to benefit from sustained strong growth in the nascent hard seltzer category that could post +30% CAGR over the next five years."