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What: Shares of network gear maker F5 Networks (FFIV -0.27%) plummeted 19% today after its preliminary quarterly results disappointed Wall Street.

So what: F5 shares have been battered over the past year on concerns over slowing growth, and today's second-quarter warning only reinforces those worries. While management blamed the downbeat view on weak industry conditions, analysts believe that F5 is losing market share to the likes of Citrix Systems and Radware, giving investors plenty of bad vibes about its competitive position going forward.

Now what: Management now sees second-quarter adjusted EPS of $1.06 or $1.07 on revenue of about $350.2 million, well below its prior view of $1.21-$1.24 and $370 million-$380 million. "Currently, we are looking into all the factors affecting the quarter's results and we plan to provide more color during our regularly scheduled release and conference call on April 24," said CEO John McAdam. Given the large amount of industry and competitive uncertainty surrounding F5 at this point, Fools would do well wait for those details before even considering a turnaround bet.

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