It's been a rough ride for Green Mountain shares over the past few months.
NEW YORK (CNNMoney) -- Green Mountain Coffee Roasters shares plummeted in late trading Wednesday after the company reported quarterly revenue that missed estimates and lowered its guidance for 2012.
Green Mountain (GMCR) shares sank more than 40%, dipping below $30 after closing earlier in the day at $49.52.
The company's quarterly earnings came in line with expectations at 64 cents a share, though its $885 million in sales missed estimates of $972 million.
Green Mountain also reduced its fiscal 2012 sales guidance from between $4.3 and $4.5 billion to between $3.8 and $4 billion. The full-year earnings-per-share projection was cut from between $2.55 and $2.65 to between $2.40 and $2.50.
In a conference call with analysts, Green Mountain executives said they didn't have a full explanation for why sales were weaker than expected. They suggested that low brewer machine sales and weak demand for holiday drinks during the warm winter -- like cider and hot cocoa -- were partially to blame.
"We're very positive about this business going forward, but there's a lot of moving parts," Green Mountain CEO Larry Blanford said.
Green Mountain currently dominates the single-serving coffee market with its popular Keurig, or K-Cup, machines.
It was one of the fastest-growing companies of the past decade and one of the best-performing stocks, handing investors 110% gains on an annualized basis until last fall.
Things changed in October, when hedge fund manager David Einhorn of Greenlight Capital outlined a case for why Green Mountain would see its market share crumble, citing its expiring patents. He also raised concerns about the firm's accounting.
More recently, Green Mountain's stock took a hit after Starbucks (SBUX, Fortune 500) unveiled its own single-cup home-brewing machine. Shares gained some of this ground back after the two companies announced they were joining forces to sell Starbucks-branded single-serving coffee packs for Green Mountain's newest coffee machine, the Vue.
Green Mountain and Starbucks first paired up to sell Starbucks' coffee in Green Mountain K-Cup machines in March 2011.
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