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.

While the past week wasn't the worst in August -- which itself has been the worst month this year for the Dow Jones Industrial Average (DJINDICES:^DJI) -- it also wasn't a very good one. The blue-chip index lost 200 points, or 1.33%, over the past five trading days, making it the third worst week of the month. The Dow now sits at its lowest level since late June, at 14,810.

The S&P 500 also had a rough week, down 1.83%, while the Nasdaq was, by a hair, the worst index performer this week, losing 1.87%. This week brought additional fears of a Federal Reserve taper, volatile interest rates, poor housing data, and the possibility of an American military attack in Syria. Combined with an extreme level of uncertainty, these events could continue to put pressure on the markets during the coming trading sessions.

Before we hit the Dow losers, let's look at this week's best-performing component. With an increase of just 0.81%, Home Depot (NYSE:HD) didn't have the kind of performance you'd expect from the index's leading performer, but that's what happens when only two of the Dow's 30 components managed to end the week higher -- the other being Chevron at 0.75% -- as the fears of possible military action in Syria sent oil prices higher.

As for Home Depot, the specialty retailer was one of the worst performers not only two weeks ago, but three weeks ago also. After it lost 7.9% of its value following three straight weeks of declines, investors seem to have realized that at 22 times past earnings and 17 times future expected earnings per share, the stock was once again a buy. What's odd about this week's move higher, though, was that housing data wasn't great and interest rates remained about the same, in an apparent indication that some investors think the company will perform well regardless of what the housing market does in the near term.

The big losers
Alcoa
(NYSE:AA) was the worst-performing Dow component this past week, losing 4.38% of its value. The bulk of that move came on Friday, after an analyst at JPMorgan Chase (NYSE:JPM) released a report indicating that the price of aluminum will probably once again fall in the coming months from its current $250 per ton to $100, and that nearly two-thirds of the world's aluminum producers won't be profitable at that price. The analyst believes that the London Metals Exchange will approve the proposed plan to change how metals are priced. Warehouses currently hold large amounts of aluminum that aren't considered part of the current supply, therefore sending prices higher than they should be if the true supply wasn't being hampered.

While this report caused Alcoa to fall 1.41% on Friday, don't be shocked if shares rise in the coming days as investors realize that if two-thirds of the aluminum producers will fail if prices fall, those that survive should be able to thrive in the coming years as true supply and demand begin to balance out.  

Speaking of JPMorgan Chase, the bank ended the week as one of the worst components, losing 3.42% over the past five trading days. On Monday, Dick Rove at Rafferty Capital Markets downgraded the stock to a "hold" from "buy" and cut his price target on the stock from $60 to $57. Rove believes the company is dealing with a few large risks in the coming months as a result of a "government vendetta." He sees profits taking a hit as he envisions revenues declining in the investment-banking and payment-transaction parts of the business while legal fees go up.  

Lastly, shares of Microsoft (NASDAQ:MSFT) lost 3.88% this past week as more negative news of the health of the PC business hurt the stock price. On Thursday the IDC reported that emerging markets -- an area that had seen strong PC sales and was helping offset declining sales in Europe and the U.S. -- is now also experiencing a weakening demand for PCs. The report indicated that China and India are seeing increased demand for tablet computers, which is eating into sales of traditional laptops and tower PCs. Another report earlier in the week indicated that Microsoft had cut its expectations for the Xbox One from 7 million units shipped in 2013 to only 6.2 million. That could be a result of the price difference between the Xbox One and the newest Sony PlayStation console, with both devices set to be released for the holiday shopping season.  

The other Dow losers this week:

(For more information on why shares of the other losers fell lower this past week, click on the following links.)

Fool contributor Matt Thalman owns shares of Bank of America, Microsoft, JPMorgan Chase, Walt Disney, and Johnson & Johnson. Check back Monday through Friday as Matt explains what caused the Dow's winners and losers of the day, and every Saturday for a weekly recap. Follow Matt on Twitter: @mthalman5513

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