Your post demonstrates your ignorance. A GTC sell order does nothing. Shares are still shortable no matter what you do. If you have a margin account, they can & will allow your shares to be shorted. Your statement: "and not available for shorts to cover" is idiotic. The only way your shares cannot be borrowed is if you have a cash only account. "Not available for shorts to cover"? Too funny. You can always cover your short shares by buying them back. Nothing you do can prevent this.