Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

Wednesday's stock market moves resembled a roller-coaster ride, with an initial gain giving way to losses for major-market indexes as news from the Fed failed to inspire bulls to buy stock. For Potbelly (PBPB 2.30%), SM Energy (SM 1.58%), and Navios Maritime Holdings (NYSE: NM), though, the losses were much more dramatic than those of the overall market.

Potbelly fell almost 9% as the newly public sandwich-restaurant chain disappointed investors with its quarterly results. Same-store sales growth of 0.7% wasn't nearly enough to satisfy shareholders, given the stock's pricey valuation. Moreover, even adjusting for the expenses of going public, profits fell around 20% from year-ago levels. Forward guidance looked equally gloomy, as the same poor weather that hurt results in the fourth quarter have persisted this quarter as well. After the drop, some investors are starting to consider Potbelly from a value-stock perspective, but high-growth investors are nervous about its future.

SM Energy plunged 17% after announcing its fourth-quarter results last night. The exploration and production company's average production figures were within the guided range, but costs were higher than expected, disappointing investors despite a near tripling of adjusted net income from the year-ago quarter. In addition, concerns about the stock's continued ability to produce more lucrative oil and liquids at its Eagle Ford wells led analysts at KeyBanc to downgrade the stock as well. One big question going forward is whether SM Energy can take advantage of rising natural gas prices, as that could be a further opportunity for the company.

Navios Maritime Holdings dropped 12% as the shipping company missed earnings estimates in its fourth-quarter report this morning. Despite efforts to keep costs under control, Navios' adjusted net loss ballooned to more than $18 million, up from just $1 million in the year-ago quarter. But revenue from its drybulk vessel operations jumped 14%, with improving time-charter equivalent rates pointing to a potential rebound in the long-suffering shipping industry. Still, falling revenue from Navios' logistics business weighed on the company's results, and Navios needs to make further progress in order to convince investors that the shipper is back for good.