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.

The first month of 2014 brought some of the coldest winter weather we've seen in years; still not content with the misery it was causing, when the closing bell rang today, January went down as the worst month for the Dow Jones Industrial Average (DJINDICES:^DJI) since May 2012. The blue chip index is down more than 5.3% for the year. Wall Street again seized on emerging markets fears as the Dow slumped 149 points, or 0.9%, to end at 15,698. 

Pulling back 0.8%, Walt Disney (NYSE:DIS) stock was in good company with its blue chip peers today, when 25 of the Dow's 30 components lost ground. The downtick is nothing to be worried about, especially considering the stock's outperformance yesterday and the market's overly bearish mood, in general, on Friday. A more immediate concern for Walt Disney is the pesky, Barry Diller-backed private company Aereo, which markets a service that picks up TV broadcast signals with tiny antennas. But tiny antennas aren't the problem; Aereo's business model is. The company doesn't pay a dime to the broadcasters of the content. Earlier this month, the Supreme Court agreed to hear a suit brought against Aero by major broadcasters. It's a safe bet that Disney's rooting for the broadcasters in this battle.

Arcos Dorados Holdings (NYSE:ARCO), which is the world's single-largest McDonald's franchisee, saw shares slump 4.8% today. January hasn't treated Arcos Dorados shares well either: the stock is off 26.9% this month alone. A serious concern for investors going forward will be the health and stability of emerging markets, which have been quite turbulent since data showed China's manufacturing sector contracting last week. Arcos Dorados is hyperfocused on Latin America and the Caribbean, but if currencies in emerging markets all around the world continue weakening indiscriminately, Arcos Dorados could be in hot water.

Finally, shares of Best Buy (NYSE:BBY), which ended as some of the worst performers in the whole market on Thursday, suddenly bounced back today, tacking on 3.6% to close out the week. While Best Buy will be trimming 950 employees from its Canada locations, the big-box retailer hasn't announced plans to close any of its stores. While the company isn't exactly prospering right now, it's not in its death throes, either, and this year should be a fairly monumental one for the business as it adapts to an entirely reshaped competitive environment.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.