NEW YORK (TheStreet) -- Shares of Zulily Inc. (ZU)  are up 5.36% to $38.50 in pre-market trading after Goldman Sachs (GS) - Get Report upgraded its rating to "buy" from "neutral" with a price target of $50.00 versus $47.00, as it cited higher than expected customer growth in 2015.

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STOCKS TO BUY: TheStreet Quant Ratings has identified a handful of stocks that can potentially TRIPLE in the next 12 months. Learn more.