The markets received very little economic news today, and perhaps that's why the Dow Jones Industrial Average (DJINDICES:^DJI) moved so very little. The index closed the day just slightly higher, up 3.76 points or 0.03%, and now sits at 13,025. Only 18 of the Dow's 30 components ended the trading session in the green, and we can blame the Dow's poor performance on a number of different companies, which I have done today. This afternoon I discussed why Merck (NYSE:MRK), Microsoft (NASDAQ:MSFT), and Travelers (NYSE:TRV) all moved lower. Read about what caused those four companies to fall into the red by clicking here or stick around to learn why Du Pont (NYSE:DD), Caterpillar (NYSE:CAT), and Cisco (NASDAQ:CSCO) also moved lower.

So why did they fall?
Earlier in the week it was announced that Du Pont lied to a federal court and investors. The fraud was committed during a patent lawsuit in which Du Pont claimed it had the right to use seed technology designed and owned by Monsanto (NYSE:MON). Shares dipped on Wednesday, but they opened on Thursday right about where they closed on Tuesday. Today, shares slid 0.92% and into the low $43 range, nearly were they traded on Wednesday. The lawsuit is turning into quite the disaster for Du Pont and its shareholders, and potential new investors should hold off until these issues are handled.

The second worst performing Dow component today was Caterpillar, as shares slid lower by 1.17%. With no negative news pertaining to the company today, and as my Fool Colleague Dan Caplinger noted this morning, the company tends to move up or down based on the almost daily economic indicators that investors attempt to use to understand the current health of the economy. Long-term shareholders should just consider these daily moves up and down the norm, at least until Washington agrees on a solution for the upcoming fiscal deadlines.

Just yesterday, Cisco made its third acquisition announcement in November. The press release yesterday stated that Cisco will pay $141 million for systems networking company Cariden Technologies. This purchase brings Cisco's spending spree in November to almost $1.5 billion. Yesterday, when the announcement was made, shares of Cisco were up, but perhaps after sleeping on the news, investors began to feel differently about the purchase, and shares closed the day down 0.53%.

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.