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 Ariba (Nasdaq: ARBA) soared as much as 16% in early trading on heavy volume, after German software supplier SAP (NYSE: SAP) announced plans to acquire online HR specialist SuccessFactors (Nasdaq: SFSF) for $3.4 billion.

So what: Issues notwithstanding, Ariba could enjoy a similar takeout bid. The one-time dot-com darling continues to make a good living supplying online tools for sourcing supplies, technology, and the like. SAP and Oracle (Nasdaq: ORCL) are its top competitors.

Now what: What would its larger rivals pay? SAP is bagging SuccessFactors for about 7.6 times sales; Ariba trades for 6.3 times sales as of this writing. The delta could make for an interesting arbitrage opportunity -- but only if you believe an acquisition is inevitable. What's your take? Would you buy shares of Ariba at current prices? Please weigh in using the comments box below.

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Fool contributor Tim Beyers is a member of the Motley Fool Rule Breakers stock-picking team. He didn't own shares in any of the companies mentioned in this article at the time of publication. Check out Tim's portfolio holdings and Foolish writings, or connect with him on Google+ or Twitter, where he goes by @milehighfool. You can also get his insights delivered directly to your RSS reader.

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