It would have been nice if they gave the historical ratio (short as percentage of daily trading or all outstanding shares). Right now it is not even at the level of one half day of volume. One can make an argument, that in view of the prevalence of hedge funds, the ratio is actually very low. The hedgies are ot laying shorts as "bets" on a decline, but as hedges on other positions in the same sector. For instance, they may go long KLAC and short NVLS (or vice versa) just to capture the differences in volatility.
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