As I write this in the pre-market, I'm wondering what sort of trading day we will see at the Chicago Mercantile Exchange Holdings (NYSE:CME). Growth is still torrid, yes, but the company slightly missed the earnings estimate, and revenue per contract continued to slide. In the past, that's meant a swift drop in the stock price, followed by an eventual recovery. (Editor's note: The stock started the day down 3%.)

It looks as if business was very good for the second quarter. Reported revenue was 28% higher than in the year-ago period; average daily volume grew another 33%. Margins improved again, and the company posted 44% growth in net income.

Rate per contract will likely get a lot of attention. For the third quarter in a row, the Merc saw a lower average rate per contract -- whether or not the low-priced TRAKRS futures are excluded. Some of this is, of course, due to higher participation from members (who pay less than non-members). In a broader sense, though, it is also the eventual reality of a competitive market. Nobody pays as much today in commissions for anything as they did 10 or 20 years ago, so why should the Merc be immune to that?

As mentioned, volume is still exceptional. While volume growth in commodities was "only" 12%, that's a tiny part of the Merc's business. In terms of the products that feed the bulldog, interest-rate daily volume was up 36%, equity E-mini volume was up 21%, and foreign exchange volume was up 89%. At the bottom line, not only are more people trading through the Merc, but they're also trading more often, and that's certainly good for business.

From my generally value-conscious perspective, the Merc looks like an awesome business but a less awesome stock. While the trailing P/E is actually less than the trailing growth rate for this quarter, it's still hard for me to look at the valuation and see an eye-popping bargain. A downdraft in the stock might offer up a buying opportunity for aggressive investors, but less experienced investors might do well to remember that high-price/high-performance stocks are not generally the safest and most stable picks in the market.

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Fool contributor Stephen Simpson has no financial interest in any stocks mentioned (that means he's neither long nor short the shares).