Do you mean NSS and short as per the following definitions?
This is my understanding of the two definitions.
Short = reported shorting activity as per SEC reporting requirements. Activity is covered 1:1 with each activity by an issued share.
NSS= Stock shorting activity that is not covered by a 1:1 transaction. Basically the activity is not covered by loans or straddles of issued shares so somebody is trading phantom amounts of shares. Creating shares out of thin air.
***A straddle is when the same person owns the stock and is shorting the same amount or less. So it is a covered legal transaction.
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