"Don't invest more than you can lose. The market is a risky place."

Sound familiar? When I became interested in investing, my grandmother, who had done fairly well with her investments, gave me that very advice. Of course I didn't want to lose money (who does?), so I did some reading and quickly came across the idea of a "stop-loss" order. This type of order automatically sells the stock if the price drops to a certain level or by a certain percentage.

"What a great idea!" I thought to myself. "Something that limits my downside!"

For many investors, the proxy for risk is volatility. The thinking goes that if you don't want to lose money (and not losing money is Warren Buffett's first rule of investing), you should try to minimize volatility. And since a stop-loss order gets you out when the price goes down, many investors employ stop-losses to avoid losing money.

The dangers of stop-loss
But let's see how that idea works in practice. Here's a table showing the returns you would have if you'd bought the following companies on Jan. 2, 2003, and then sold after the first 15% decline (we've also included how long that took). Compare that with the returns if you had just held on through the bad times, including the downturn this year, up through the end of last month.

Company

With 15% Stop-Loss
(Time to Sale)

Without
Stop-Loss

Boeing (NYSE: BA)

(13.2%) (5.8 weeks)

145.5%

Harley-Davidson (NYSE: HOG)

(12.3%) (2.7 weeks)

(15.5%)

Goodyear Tire & Rubber (NYSE: GT)

(11.3%) (3.6 weeks)

259.0%

Hilton Hotels

(14.2%) (3.6 weeks)

255.5%*

JPMorgan Chase (NYSE: JPM)

(5.5%) (3.2 weeks)

86.3%

Medtronic (NYSE: MDT)

(3.6%) (9.1 months)

(0.4%)

Texas Instruments (NYSE: TXN)

16.5% (5.3 months)

93.0%

*Hilton Hotels was purchased by the Blackstone Group (NYSE: BX) on 10/24/07 for $47.50 per share. Return is calculated through that date.

Doesn't compare too favorably, does it? Rather than limiting downside, the stop-loss seems to be limiting upside ... and this table isn't limited to outlandish winners.

Wait a second ...
I can hear some people saying that it's possible to get back in when the stock begins to go back up. But how would you know when to get back in? And even if you did, no stock climbs steadily upward. Goodyear, for example, would have triggered sales eight separate times in 2003 alone using a 15% stop-loss strategy.

Furthermore, trades cost money. You've paid commissions to repurchase the shares, as well as the commissions for every stop-loss sale. Both eat into your overall returns. And note that every single one of those sales came within a year of buying, potentially triggering short-term capital-gains taxes on each. That hurts.

The only real winners in this scenario are your broker and the IRS.

Try this instead
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This article was originally published Sept. 9, 2006. It has been updated.

Jim Mueller owns shares of Harley-Davidson, but no other company mentioned. JP Morgan is an Income Investor pick. The Fool has an ironclad disclosure policy.