Its shares dropped 10 percent, bringing their loss this year to 23 percent, with at least four analysts cutting their price targets for the stock after the company late said on Thursday its first-quarter net revenue fell 5 percent year-over-year to $189 million.

IPAs, pilsners, porters and stouts brewed by small regional brewers have become wildly popular in the United States in recent years, leading heavyweights like Anheuser Busch Inbev SA to increase their own higher-quality offerings.

In the March quarter, Boston Beer launched Samuel Adams Nitro White Ale, Samuel Adams Nitro IPA, Samuel Adams Nitro Coffee Stout and Samuel Adams Rebel Grapefruit IPA.

But those new beers were not enough to fend off competition from rivals and the company said it expects its shipments to fall between 2 percent and 4 percent this year.

On a conference call with analysts, Boston Beer Chairman Jim Koch estimated that as many as 4,800 craft brewers are operating in the United States, a number he said could dramatically increase. But he warned that the market may already be near saturation.

"The gating mechanism will probably be retailers reaching the point where adding more tap lines does not add to the craft beer sales," Koch said.

Following Boston Beer's report, Cowen and Company Susquehanna, RBC and Jefferies cut their price targets for the stock.

Analysts had expected first-quarter revenue of $198 million, according to Thomson Reuters data. EPS was 53 cents, far below the 96 cents Wall Street expected.

The company's stock recently traded at about 22 times expected earnings, below its five-year average of around 25. Molson Coors Brewing Co trades at about 25 times earnings.

(Reporting by Noel Randewich; Editing by Dan Grebler)

By Noel Randewich