Ieri sul New York Times una lettera di un tizio che dovrebbe saperla lunga:

http://it.wikipedia.org/wiki/Warren_Buffett

By Warren E. Buffett

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A simple rule dictates my buying: Be fearful when others are greedy, and be greedy when others are fearful.
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What is likely, however, is that the market will move higher, perhaps substantially so, well before either sentiment or the economy turns up. So if you wait for the robins, spring will be over.
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In short, bad news is an investor’s best friend.