NEW YORK ( TheStreet) -- National Coffee Day is spurring a spike in Internet searches today as consumers clamor to find out if their favorite java joints will be celebrating with a free cup for patrons.

Several coffee chains across the U.S. are joining the festivities by offering free coffee promotions. Participating Dunkin Donuts locations are giving customers one free cup of coffee, and will donate some of the proceeds from sales of other items to Special Olympic groups. LaMar's Donuts and Coffee will give customers who present this printable coupon a free cup of coffee, and Java Café is offering customers a 50% discount on drinks from 7 A.M. to 12:00 P.M. today.

But it's not all good for coffee companies today. Green Mountain Coffee Roasters ( GMCR) shares plunged after the Securities and Exchange Commission probed the company on its revenue recognition practice.

In a 8-K filing, Green Mountain said that based on the SEC request of specific documents and information, it believes the inquiry concerns its revenue recognition practices as well as its relationship with one of its vendors.

The SEC inquiry came after Green Mountain's management discovered an "immaterial accounting error" relating to the margin percentage it had been using to eliminate the inter-company markup in its K-Cup inventory balance at its Keurig business unit.

Green Mountain shares are down 16.4%, to $30.94.

-- Written by Theresa McCabe in Boston.

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