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 sandwich-shop operator Potbelly (NASDAQ:PBPB) soared 13% today after its quarterly results and outlook topped Wall Street expectations.

So what: The stock has been sluggish since its IPO in early October, but a delicious first report -- third-quarter adjusted profit surged 26.7% on a revenue jump of 11.7% -- coupled with upside guidance is prompting investors to quickly raise their growth estimates. In fact, same-store sales increased 2.5% while shop-level profit margins expanded 50 basis points, giving analysts plenty of good vibes over its competitive positioning, as well.

Now what: Management now sees full-year adjusted EPS of $7.5 million to $8.1 million on revenue of $300 million to $303 million. "We view the IPO as a significant milestone, but not a destination," said Chairman and CEO Aylwin Lewis. "Our focus remains on operating the business and delivering long-term shareholder value." More important, with the stock still off more than 10% from its IPO-day high, there might be room left to benefit from that bullishness.