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.

Today, two of the three major indexes moved lower as trading volumes hit their lowest levels of the year. The 2013 average trading volume on U.S. exchanges is around 6.4 billion shares, but today we saw only 4.6 billion shares trading hands. The Dow Jones Industrial Average (DJINDICES:^DJI) closed lower by 46 points, or 0.3%, and now sits at 15,612, while the S&P 500 (SNPINDEX:^GSPC) lost 0.15%, but the Nasdaq rose 0.09%.

The light volume shouldn't surprise anyone, as last August also saw the year's lowest trading volume and many Americans vacation this time of year. Likewise, the fact that four of the five most shorted Dow components also declined today shouldn't have raised many eyebrows. It only makes sense that a stock that's fallen out of favor with investors would lose ground on a day like this.

So who were the big losers today?

Shares of Caterpillar (NYSE:CAT) lost 0.88%, making it the fourth worst Dow stock of the day. Caterpillar is currently the third most shorted component, with 3.69% of shares outstanding sold short, as the world's mining industry continues to experience slow growth and commodity prices have shown weakness.

Intel (NASDAQ:INTC) is another heavily shorted stock, with 4.87% of shares outstanding sold short. The stock lost 1.27%, probably because the stock went ex-dividend today -- when the share price is adjusted lower by the amount the company pays out in its dividend. In Intel's case, the company pays a quarterly dividend of $0.225 per share, so the share price opened lower by that amount this morning when trading began, completely apart from any negative news or opinions about the stock.

Despite not being a heavily shorted Dow component -- with only 1% of float sold short -- shares of United Technologies (NYSE:UTX) lost 1.05% today. Similar to Caterpillar, the company is facing a number of headwinds as the world's economies are slowing, but United Tech's biggest problem is sequestration. Shares are still trading close to their 52-week high of $107.86 and currently sport a price-to-earnings ratio of 15.44, with an expected forward P/E of 15.3. So while the stock was the worst-performing Dow component of the day, if the federal government can figure out a way to reduce some of its cuts or United Tech can find revenue from its other businesses, shares could perform extremely well in the future.