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 divergence among stock market indexes that investors saw on Friday continued today, but it reversed direction as the Dow dropped while broader-market measures rose. Earnings season produced some mixed results, but for Dow Chemical (NYSE:DOW), BlackBerry (NYSE:BB), and Alcoa (NYSE:AA), Tuesday produced some impressive gains, especially given the extent to which BlackBerry and Alcoa have suffered over the long run.

Dow Chemical gained almost 7% after activist investor Dan Loeb and his Third Point hedge fund revealed that the chemical giant was its largest position. Following the trend of DuPont (NYSE:DD) and other chemical companies to emphasize their most profitable business segments, Dow said last month that it would seek to sell off much of its legacy chlorine business, which suffers from low margins. But Loeb reportedly wants a more dramatic shift, splitting Dow Chemical into a petrochemical company and a specialty-chemicals company that would focus on higher-margin opportunities. Investors believe that Loeb has the track record and determination to make shareholder-enhancing moves happen.

BlackBerry climbed another 9%, adding to its gains from Friday after the company earned a big vote of confidence from the Pentagon. The Defense Information Systems Agency will use 80,000 BlackBerry phones, making up all but 2% of unclassified mobile devices under its mobile program. After the bell this afternoon, BlackBerry also said that it would sell off its Canadian real estate, seeking to unlock value by working with real-estate company CBRE (NYSE:CBRE) to do sale-and-leaseback transactions for some of its property and outright sales for the rest. The moves highlight the efforts that BlackBerry is making to maximize value for shareholders even as many believe that its days as a mobile-device maker are numbered.

Alcoa gained 7% as it earned a huge upgrade from analysts at JPMorgan Chase. The firm almost doubled its earnings estimate for Alcoa's 2014, raising its price target to $15 and arguing that anticipated levels of surplus aluminum supply would be far lower than previously expected. The big wildcard in aluminum is the extent to which China could cut back on exports. Ever since Alcoa left the Dow, its stock has climbed impressively, suggesting that the worst times for the commodities industry might be coming to an end.

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