It is I who needs to thank you Golf....last year it was your eagle eye that first spotted these house 100 'out of bounds' trades that were taking place at about 3pm each day for a protracted period of time....when I found out these TSX Buy-Ins were due to 'fails to deliver' I knew right away it was about Naked Short Selling, something I've read a lot about.    

While you are correct, that these delivery failures show us that there are basically zero shares available to borrow in margin accounts....that doesn't mean moving shares from a margin to a reg'd account won't cause some consternation for short sellers.

Right now if someone has say 50,000 shares sitting in a margin account....there's no way for that shareholder to know if his/her shares have been loaned out, everything is electronic now.  I suspect that, while the account will still show 50K shares, that there's an IOU attached to them if they have been loaned out.  The owner of the 50K shares can still sell if he/she wants....in that case I assume the IOU then just passes from the seller to the buyer.

However moving 50K shares from a margin account to a reg'd account is a different matter.  To move the shares into a TFSA/RSP account, those shares would need to have a certificate number attached, not an IOU.  Conceivably it could force the borrower of those shares to have to buy them in the market....which should increase buyside pressure on RVX and would hopefully lead to the PPS climbing.