Tech stocks had a generally positive week last week, heading into the middle on June. But these three tech tickers ended up swimming against the stream, and not in a good way:

  • Hydrogen fuel cell producer Plug Power (NASDAQ:PLUG) gently swooned 5.5% lower, in spite of any obvious value-destroying news. When you're as hyper-volatile as Plug Power, those are the breaks sometimes.
  • NQ (NYSE:NQ), which provides mobile Internet services for Chinese customers, fell 15%. The memory of NQ's positive fraud investigation news from the previous week is fading -- and NQ investors are getting restless.
  • Finally, optical networking expert Finisar (NASDAQ:FNSR) plunged 20% in one terrifying night. Shareholders came into this report with high expectations, given the strong report from Finisar customer Ciena (NYSE:CIEN) the previous week. But fourth-quarter earnings disappointed, and management guidance didn't help to calm any nerves.

Two of these stocks seem destined for extreme volatility and uncertain long-term returns. The third one might be both undervalued and delicious.

Find out more in the slideshow below.

Anders Bylund has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days.

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