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What: Shares of Universal Display (NASDAQ:OLED) went dark today, down by as much as 16% after bearish comments from an analyst sparked competitive fears.

So what: Piper Jaffray analyst Jagadish Iyer believes that Universal Display's relationship with Samsung is under pressure, as the South Korean conglomerate may have tapped a second supplier for OLED emitter materials. Nippon Steel Chemical may have been able to cut in and earn some of Samsung's business, and Samsung's efforts to improve production efficiency could also translate into lower materials purchases.

Now what: Iyer still believes that Samsung will use UDC's ingredients for the OLED display expected in the next-generation Galaxy S IV, which is to be unveiled on March 14. That contrasts with rumors from SamMobile that the company may not be using OLED in the display due to challenges producing them at full HD resolutions. Iyer is maintaining a sell rating, while reducing his price target from $18 to $16. Universal Display reports earnings on Wednesday.

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Fool contributor Evan Niu, CFA, owns shares of Universal Display. The Motley Fool recommends Universal Display. The Motley Fool owns shares of Universal Display. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.