...when they ban short-selling. As a response to economic problems, banning short selling is roughly equivalent to banning criticism of the government during a political crisis. Or perhaps more accurately, its like trying to improve poll results by not polling people with negative opinions. Short-selling has utility for the actual traders involved because it helps them achieve whatever financial or risk-management goals they might have. Short-selling has utility for the rest of us because it allows the full range of opinions to be expressed about the value of a particular company or asset. Nothing in a market economy is worse than having prices that have no meaning.