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.

U.S. stock markets reached intraday record highs Monday as investors piled into equities, driving the Dow Jones Industrial Average (DJINDICES:^DJI) above 16,000 briefly and the S&P 500 (INDEX: ^GSPC) above 1,800 before both retreated. By the end of the day, much of the optimism had reversed. Activist investor Carl Icahn displayed his power to move markets, as the Wall Street legend expressed wariness over investing in today's market, causing markets to hastily pull back. While investors took Icahn's warning to heart, sending six in 10 stocks lower, the Dow was still able to tack on 14 points, or 0.1%, to end at 15,976.

The telecom sector was the only area of the markets to advance Monday, evidencing Wall Street's relatively risk-averse mentality today. Telecom and utilities stocks, which often have relatively predictable cash flows and pay handsome dividends, are considered "defensive" havens for times of uncertainty. McDonald's (NYSE:MCD), though not a telecom or utility, is about as tried and true as companies get nowadays. Stock in the globally recognized fast-food restaurant added 0.8%, despite little company-specific news driving the advance. Low-risk investments such as U.S. Treasuries advanced today, driving yields on the 20-year treasury to 3.46%. Meanwhile, McDonald's rewards investors to the tune of a 3.3% annual dividend, making the stock a reasonable option for income investors looking for a little equity as well. 

E-Commerce China Dangdang (NYSE:DANG), on the other hand, is a very different type of investment from McDonald's or treasuries. As Dangdang's name implies, it's a Chinese e-retailer, a far cry from an iconic company with one of the most recognizable brands in the world. Dangdang cratered 9.2% Monday; last week it reported quarterly earnings, and shares jumped 10% on two separate occasions. Dangdang has more than doubled this year, and with the recent gains in perspective, a pullback is more than called for -- not merely because of its recent outperformance, but because the company's still not profitable and sales grew just 19% in the most recent quarter. Bottom line: Dangdang is about five times more volatile than the market itself, and putting money in this speculative foreign small-cap isn't for the weak of heart. 

Lastly, SUPERVALU (NYSE:SVU) shares slumped 8.7% Monday, ending as one of the most notable decliners in the consumer services sector. The U.S. grocer, which owns more than 380 Save-A-Lot stores and licenses nearly 1,000 more to independent operators, is highly dependent upon a less prosperous customer base. Goldman Sachs downgraded SUPERVALU shares today on cuts to food stamps, or the SNAP program, that went into effect on Nov. 1 as the federal stimulus program winds down.