RE:RE:RE:RE:RE:RE:Short SqueezeBetter description than goldy's. But your broker cannot lend your shares unless you have a margin account AND you have borrowed money from them to buy the shares. Check with IIROC. They are VERY adamant about this rule. When a mutual fund company or pension fund manager randomly calls the custodian demanding all their client's shares be returned by end of day they usually offer double or triple the fees to let it ride. Counterintuitively perhaps but high volume days lead to more calls to cover if the volume is real trading from mutual fund A to pension fund B because A may be a lending client, and B may not. It takes a day, sometimes 2, for the dust to settle through clearing houses. It's part of the reason same day settlement of stock trades is not yet a reality.