DOW JONES NEWSWIRES Green Mountain Coffee Roasters Inc. (GMCR) agreed Tuesday to sell Dunkin' Donuts coffee in its proprietary single-cup servings, the latest move in an increasingly competitive market for individual coffee portions. Financial terms of the deal weren't disclosed. The agreement could prevent a deal between Green Mountain and Dunkin' rival Starbucks Corp. (SBUX), which had been speculated earlier this month. Starbucks has indicated it plans to enter the high-growth single-cup coffee market either through a partnership or with its own offering. Starbucks inked one partnership last week by providing coffee for up to 500,000 hotel rooms that use Courtesy Products' single-cup coffee brewers. Shares of Green Mountain jumped 2.9% to $43 in premarket trading Tuesday, while Starbucks shares were off 0.6% to $33.80 on light volume. "GMCR's agreement with Dunkin' Donuts is part of our strategy of aligning with the strongest coffee brands to support a range of consumer choice and taste profiles," Green Mountain Chief Executive Lawrence J. Blanford said in a statement. Green Mountain said Dunkin' Donuts will sell packs of 14 single-serve K-Cup servings at its coffee shops for use with Green Mountain's Keurig single-cup brewers. -By Drew FitzGerald, Dow Jones Newswires; 212-416-2909; Andrew.FitzGerald@dowjones.com