I checked this morning with CIBC Investors Edge about my cash account. I specifically asked about them lending my shares from my cash account for shorting purposes.

The answer was that if I paid for shares, they can not be used for lending to anybody.

However, when I called this afternoon, to ask about my TFSA acounts, I was told that shares in any account can be used by CIBC to lend them out for shorting purposes as long as they are over $3.00. They do not lend out shares below $3.00.

The only way to prevent the shares to be lent out is to own the actual certificates.

So, this appears to be CIBC's policy and it would be interesting to hear of other inquiries to CIBC and other institutions.