Stocks posted their best day of 2014 on Tuesday, as markets around the globe rebounded from yesterday's losses. The nascent conflict between Russia and Ukraine took an important step in the peaceful direction today, as Russia recalled some combat troops it had positioned in the region, saying it would only use force as a last resort. Jubilant investors sent the S&P 500 Index (SNPINDEX:^GSPC) to all-time highs in response, and the benchmark index added 28 points, or 1.5%, to end at 1,873. 

Advancing stocks outnumbered decliners by about a 4.5-to-1 ratio, so laggards were hard to come by today. That said, Cliffs Natural Resources (NYSE:CLF) was the single worst-performing stock in the entire S&P 500 index, slumping 2.1% on Tuesday. No matter what happens in Ukraine, if a stock is downgraded by Wells Fargo analysts -- and those analysts say your stock could lose 75% of its value unless the company restructures -- your stock is going to fall. Ignoring analyst price targets for a moment (or forever), there are two, broad issues that really matter right now for Cliffs Natural. "What will the price of iron ore do?" and "What will the restructuring look like if the company does restructure?"

Shares of computer security software company Symantec Corporation (NASDAQ:SYMC) dropped 1.8% in trading today, as investors cautiously reacted to an executive shakeup. Previously serving in both the role of CFO and CEO at Advanced Micro Devices, Thomas Seifert will be taking over the CFO and executive vice president roles at Symantec beginning March 17. Seifert's experience at one of the most prominent mobile chip providers in the world should give Symantec some useful insight into an area of growth begging to be monetized more aggressively: mobile device security.

Speaking of new frontiers in technology, even large retailers like Best Buy (NYSE:BBY) are still trying to figure out how to rake in the dough from -- it's pitiful, I know -- online sales. While Best Buy stock rallied 8% last week, partly on the 25% growth of its holiday quarter's online sales, shares lost 1.3% on Tuesday, a poor enough performance to land it on this list. While Best Buy swung to a profit last quarter, its same-store sales were also down, which means that the electronics retailer continues to struggle with soliciting foot traffic. Even if the company's more than a decade behind its larger peers when it comes to e-commerce dominance, it's better late than never!