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 of young-adult clothing retailer Express (NYSE:EXPR) climbed 10% today after its quarterly results and outlook topped Wall Street expectations.

So what: The stock has rallied nicely over the past year on better-than-expected growth, and today's second-quarter results -- both earnings and revenue rose 7% -- coupled with upside guidance for the full year suggest that the trend isn't slowing. In fact, same-store sales during the quarter increased 6% over the year-ago period, giving analysts plenty of good vibes over its competitive position and ability to grow profitably.

Now what: Express now expects full-year EPS of $1.52 to $1.60, up from a prior view of $1.48 to $1.58, and sees same-store sales growth in the low to mid single digits. "Our customers are responding enthusiastically to our assortments, which are trend-right, differentiated and well-edited," said Chairman and CEO Michael Weiss. "As we move into the second half of the year, we are confident in our product and marketing strategies, and believe we are well positioned for the fall and holiday seasons." With the stock now up about 110% over its 52-week lows, however, much of that optimism might already be baked into the valuation.