JBII is *NOT* on the REG SHO list. Means it's not naked shorted at all.
Regulation SHO also created the "Threshold Security List," which reported any stock where more than 0.5% of a company's total outstanding shares failed delivery for five consecutive days.
The reason for 50%+ shorts on the list are due to T+3 Delivery:
The Securities Exchange Act of 1934 stipulates a settlement period up to three business days before a stock needs to be delivered,[13] generally referred to as "T+3 delivery."