You don't have to be Sir Isaac Newton to know that in investing, as in physics, what goes up must come down. If your portfolio is full of stock mutual funds that have launched into the stratosphere over the course of the bull market, no one would blame you for searching the sky for rapidly descending apples. The potential headache: A 50% decline in an investment requires a 100% gain just to break even.

Mutual funds can't repeal the laws of physics. But over full market cycles, they can beat their benchmarks--even if they trail them during bull markets--by playing good defense when it counts. Here are five funds that have stood out over the long term by losing less during down markets.

American Funds Washington Mutual F-1

Ticker: WSHFX

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