Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Acme Packet (Nasdaq: APKT) rose 11% in early trading and remain up more than 10% as the closing bell approaches. Analysts at Stifel Nicolaus upgraded peer F5 Networks (Nasdaq: FFIV) from hold to buy, lifting not just F5 but also a number of related stocks.

So what: Interestingly, F5 is moving only half as much as Acme Packet today. What gives? I can't be sure, honestly, but it's possible that Big Money investors have decided last week's broad-brush downgrade of networking stocks unfairly included Acme Packet.

Now what: At least that seems plausible, unlike Pacific Crest's lumping Acme Packet in with the likes of Juniper Networks (Nasdaq: JNPR) in a mass downgrade of communications equipment stocks. This, after all, is the same company that grew both revenue and normalized net income by 49% last quarter on expanding gross margins and higher market share. Growth stories don't get much better than that. Do you agree? Would you buy at these levels? Weigh in using the comments box below.

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