The Dow Jones Industrial Average is a collection of 30 large and widely held U.S.-based companies that acts as a bellwether for the overall stock market. While the index has lost 14% in the month of October, its bottom 10 companies have seen their stock prices fall even further.

Of course, a stock's price can drop for reasons both significant (e.g., the emergence of a more powerful competitor) and insignificant (e.g., tax selling). Hence, a large drop in stock price could offer a unique buying opportunity, but it could also present a value trap.

That's why we've paired the 10 biggest Dow losers for the month of October with the intelligence of our 120,000-member-strong Motley Fool CAPS community. Each company's CAPS rating should offer some insight into how our community views the company. As always, though, you should conduct your own fundamental research.

For the month of October, here are the Dow's ten biggest market losers:

Company

Return in October

Year-to-Date Return

CAPS Rating (out of 5)

1. Alcoa (NYSE:AA)

(45.9%)

(68.5%)

***

2. Citigroup

(40.7%)

(53.6%)

**

3. General Motors (NYSE:GM)

(38.7%)

(76.7%)

*

4. Bank of America (NYSE:BAC)

(36.6%)

(41.4%)

***

5. Caterpillar (NYSE:CAT)

(32.9%)

(47.4%)

****

6. American Express (NYSE:AXP)

(22.2%)

(47.1%)

***

7. DuPont (NYSE:DD)

(20.8%)

(27.3%)

*****

8. General Electric (NYSE:GE)

(20.4%)

(47.4%)

****

9. Coca-Cola

(18.6%)

(28.2%)

****

10. JPMorgan Chase

(16.9%)

(5.5%)

***

Source: Capital IQ and Motley Fool CAPS.

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