if shorts want to cover, they obviously need to pay a bit more...

if shorts want to cover, they obviously need to pay a bit more at this time ? ? Depends at what price they shorted. If some one shorted at 3.00 or above, he/she still sitting at margin profit. My guess is those large shorts which shows as percentage were done around $3/share or above.
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Also those who do big shorts they cover it through options.
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Law of Market is : 92% of the time it is Mum & Dad who looses not Big Fellow as they have appetite to wait for years (because they are playing with Other People's Money)