When a stock plummets to multiyear lows, it's typically not a good sign for the business and its investors. It can signal that there's something deeply wrong with the business, its fundamentals, future, or all of the above.

If it's just a 52-week low, that may not be all that bad. But the longer back you have to go to find the last time the stock traded at its current levels, the worse the situation usually is. In some cases, however, the market can overreact and punish a stock excessively. In those circumstances, it could make for an attractive contrarian investment .

One stock that's been down big of late is FMC ( FMC +1.83% ) . This year, it has lost more than 70% of its value. The sell-off has been so extreme that the stock is now trading at levels it hasn't been at since 2

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