This morning started with concerning comments from Warren Buffett and lackluster numbers for new home sales. But while the markets opened on a down note, they ended the day on a nice upward move. Positive comments came from Washington a little after midday, and investors reacted nicely. The Dow Jones Industrial Average (INDEX: ^DJI) closed up more than 106 points or 0.83%, and now sits at 12,985. Today, only three of the Dow's 30 components ended the trading session in the red. Those lonely losers were Boeing (NYSE: BA), Cisco (NASDAQ: CSCO), and Du Pont(NYSE: DD).

So why did they fall?
Shares of aircraft manufacturer Boeing fell by 0.54%. A report by the National Transportation Safety Board released today calls for mandatory fire-suppression systems, improved fire detection, and fire-resistant cargo containers for all cargo planes operating in the U.S. While the safety board has no regulatory authority, it does have influence on new regulations within the industry, and since there have been three separate incidents since 2007 in which cargo planes have burst into flames, these recommendations will likely be heard. The proposed new regulations could cause Boeing to delay aircraft delivery in the future because of changes to current aircraft designs.

Cisco Systems became the Dow's biggest loser today as shares slid 0.68% lower. The only negative press about the company was that former McAfee president Dave DeWalt had been given the CEO job at the security firm FireEye. Some analysts had thrown DeWalt's name around as a possible future candidate for the top spot at Cisco.  

Du Pont closed down 0.46% today after little negative news about it. But the slide lower is in keeping with a recent trend for the chemical company, which has seen shares cut by 13.8% since October 1. Du Pont is also the fifth worst-performing Dow component this year, with shares down 5.55% year to date, as the index itself is up 6.28% during the same time frame  The company currently sports a price-to-earnings ratio of 13.38 and has a dividend yield of 4% at its reduced trading price. New investors, though, may be held at bay, due to the new possibly higher dividend tax rate coming in 2013.

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Matt Thalman has no positions in the stocks mentioned above, and neither does The Motley Fool. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.