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 21Vianet Group Inc (NASDAQ:VNET) fell as much as 13.4% early Wednesday, then partially recovered to trade down 8.2% as of 12:40 p.m. after the company announced weaker-than-expected first-quarter 2015 results.

So what: Quarterly revenue climbed 46.8% year over year to $138.7 million, and adjusted earnings before interest, taxes, depreciation and amortization rose 47.8% to $26.9 million. That translated to a narrower net loss of $14.3 million, of $0.22 per American depositary share. On an adjusted basis, 21Vianet achieved earnings of $0.02 per ADS. Analysts, on average, were anticipating adjusted earnings of roughly $0.03 per ADS on revenue of roughly $145 million.

Now what: Nonetheless, 21Vianet Founder and CEO Josh Chen insisted, "Our year is off to a solid start with demand for our Internet data center ("IDC") and cloud businesses driving top-line revenue growth and EBITDA expansion."

To be sure, 21Vianet expanded its data center portfolio to a total of 22,024 cabinets by the end of the quarter, or 46.1% growth over the year-ago period. The company also extended its commercial operator agreement for public cloud services with Microsoft for an additional four years, through the end of 2018. 

For the current quarter, however, 21Vianet expects revenue of RMB886 million to RMB922 million, or roughly 37% year-over-year growth at the midpoint. Adjusted EBITDA should be RMB152 million to RMB172 million, or 23% growth at the midpoint. Analysts were anticipating greater top-line growth in fiscal Q2 of 45.9%.

And for the full year fiscal 2015, 21Vianet sees revenue of RMB3.91 billion to RMB4.11 billion, or 39% growth over 2014. Adjusted EBITDA should climb 45% to RMB760 million to RMB860 million. In this case, Wall Street was expecting roughly the same results. This partially explains why the stock recovered from its more severe early morning losses.

In the end, though, while 21Vianet's growth was certainly "solid" by most measures, it's no surprise the market is bidding shares down as analysts were overestimating the company's ability to sustain its previous torrid pace. For now, until investors have time to readjust their near-term expectations, that's why I'm content watching 21Vianet from the sidelines.