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.

After a six-day rally, the major indexes calmed down today. The Dow Jones Industrial Average (^DJI 0.06%) closed lower by one point, or 0.01%, and now sits at 16,478. The other major indexes didn't perform any better as the S&P 500 lost 0.03%, and the Nasdaq closed off by 0.25%. Without a major catalyst to move stocks higher today, it seemed investors were content taking the day easy after the major indexes had rallied the previous six sessions. With limited economic data being released today, individual stocks moved largely on their own news or industry-wide events. Let's take a look at a few of today's losers that put downward pressure on the major indexes.

Shares of the social networking site Twitter (TWTR) ended the day off by more than 13% today. The move came after the stock was downgraded by analyst at Macquarie Securities. The analyst believes the stock was overvalued heading into today, and lowered the rating from neutral to underperform. Furthermore, the firm's price target of $46 remained the same, and Ben Schachter, the analyst, stated that he didn't feel anything fundamental has changed with the company recently to cause the share price to rally like it has. Heading into today, Twitter was up more than 22% this week alone, which really consisted of two-and-a-half days of trading. Investors need to be careful with this one, as it would have seemed that, heading into today, the bullish momentum had taken over and the stock was trading purely on speculation. 

Shares of Facebook (META 1.54%) also lost ground today, closing down 3.97% on very little news. Shares are up more than 122% during the past 52 weeks, which easily beats the Dow's 25% return, or the S&P 500's 31% gain. But today's decline could have been a combination of investors closing out the position before the end of the year, and a side effect from the Twitter move. Sometimes, traders, not investors, will sell competitors or a whole industry when one company is having a bad day.

Outside the social media world, shares of Delta Air Lines (DAL -0.06%) traded lower by 3.05%. The fall comes after the company had a computer glitch yesterday morning for a few hours, during which time, customers could book airline tickets for extremely cheap rates. One customer got a roundtrip ticket to Hawaii for $6.99; another got a $12.83 first-class ticket from Oklahoma City to St. Louis; while another customer got a $132 ticket from Houston to San Francisco -- which is not a great price until you consider that it's a first class ticket. The airline has not reported how many tickets were sold, and what it ultimately will cost the company, but investors seem to believe that it will show up on the quarterly statement. This is a short-term problem, and current shareholders shouldn't sell due to this issue. 

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